Neuronal helix-loop-helix transcription factor; This domain family is found in eukaryotes, and is approximately 80 amino acids in length. The family is found C-terminal to pfam00010. There is a single completely conserved residue W that may be functionally important. Neuronal basic helix-loop-helix (bHLH) transcription factors such as neuroD and neurogenin have been shown to play important roles in neuronal development.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980 147 GKRPDLLTFVQTLCKGLSQPTTNLVAGCLQLNARNFITDQINSEASFSGRSPYESVYTTYHSPGVVTPS--GPSVDAVKP 224
Cdd:pfam12533   1 GKRPDLLSFVQTLCKGLSQPTTNLVAGCLQLNPRNFLPEQMEERPGGPGSPLHPGHPYSYQSPGLPSPPygTMDSSHLLH 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|..
gi 2073702980 225 FRQFNYCSSYESFY-ESVSPECGSPQFDGPLSPPINFNGIFS 265
Cdd:pfam12533  81 LRTYGYCSPYESLYsESSSPDYYSPPYDGPLSPPLSISGNFS 122

Neuronal helix-loop-helix transcription factor; This domain family is found in eukaryotes, and is approximately 80 amino acids in length. The family is found C-terminal to pfam00010. There is a single completely conserved residue W that may be functionally important. Neuronal basic helix-loop-helix (bHLH) transcription factors such as neuroD and neurogenin have been shown to play important roles in neuronal development.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980 147 GKRPDLLTFVQTLCKGLSQPTTNLVAGCLQLNARNFITDQINSEASFSGRSPYESVYTTYHSPGVVTPS--GPSVDAVKP 224
Cdd:pfam12533   1 GKRPDLLSFVQTLCKGLSQPTTNLVAGCLQLNPRNFLPEQMEERPGGPGSPLHPGHPYSYQSPGLPSPPygTMDSSHLLH 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|..
gi 2073702980 225 FRQFNYCSSYESFY-ESVSPECGSPQFDGPLSPPINFNGIFS 265
Cdd:pfam12533  81 LRTYGYCSPYESLYsESSSPDYYSPPYDGPLSPPLSISGNFS 122

Helix-loop-helix DNA-binding domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYI 137
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYI 49

Neuronal helix-loop-helix transcription factor; This domain family is found in eukaryotes, and is approximately 80 amino acids in length. The family is found C-terminal to pfam00010. There is a single completely conserved residue W that may be functionally important. Neuronal basic helix-loop-helix (bHLH) transcription factors such as neuroD and neurogenin have been shown to play important roles in neuronal development.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980 147 GKRPDLLTFVQTLCKGLSQPTTNLVAGCLQLNARNFITDQINSEASFSGRSPYESVYTTYHSPGVVTPS--GPSVDAVKP 224
Cdd:pfam12533   1 GKRPDLLSFVQTLCKGLSQPTTNLVAGCLQLNPRNFLPEQMEERPGGPGSPLHPGHPYSYQSPGLPSPPygTMDSSHLLH 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|..
gi 2073702980 225 FRQFNYCSSYESFY-ESVSPECGSPQFDGPLSPPINFNGIFS 265
Cdd:pfam12533  81 LRTYGYCSPYESLYsESSSPDYYSPPYDGPLSPPLSISGNFS 122

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 2 (NeuroD2) and similar proteins; NeuroD2, also termed Class A basic helix-loop-helix protein 1 (bHLHa1), or NeuroD-related factor (NDRF), is a neuronal calcium-dependent bHLH transcription factor that induces neuronal differentiation and promotes neuronal survival. It plays a central role in thalamocortical synaptic maturation. NeuroD2 mediates calcium-dependent transcription activation by binding to E box-containing promoter.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980  68 PRRRGPRKKKMTKARVDRVKLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILSTG 147
Cdd:cd19720    14 PKKRGPKKRKMTKARLERSKLRRQKANARERNRMHDLNSALDNLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILRSG 93

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 1 (NeuroD1) and similar proteins; NeuroD1, also termed Class A basic helix-loop-helix protein 3 (bHLHa3), is a neuronal bHLH transcription factor involved in the development and maintenance of the endocrine pancreas and neuronal elements. It acts as an essential regulator of glutamatergic neuronal differentiation. Loss of NeuroD1 causes ataxia, cerebellar hypoplasia, sensorineural deafness, and severe retinal dystrophy in mice.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980  62 QDENGLPRRRGPRKKKMTKARVDRVKLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALS 141
Cdd:cd19719     1 EDDDQKPKRRGPKKKKMTKARLERFKMRRMKANARERNRMHGLNAALDNLRKVVPCYSKTQKLSKIETLRLAKNYIWALS 80

                  ....*.
gi 2073702980 142 EILSTG 147
Cdd:cd19719    81 EILRSG 86

tissue specific basic helix-loop-helix (bHLH-TS) domain family; Tissue specific bHLH domain family includes transcription regulators whose expression are restricted to certain tissues. They are involved in cell-fate determination and process in neurogenesis, cardiogenesis, myogenesis, and hematopoiesis and include proteins from myogenic regulatory factor (MRF) family, twist-related protein (TWIST) family, scleraxis-like family, heart- and neural crest derivatives-expressed protein (HAND) family, helix-loop-helix protein (HEN) family, musculin-like family, germline alpha (FIGLA) family, T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family, ovary, uterus and testis protein (OUT) family, mesoderm posterior protein (Mesp) family, muscle, intestine and stomach expression 1 (MIST-1) family, protein atonal homologs (ATOH) family, neurogenin (NGN) family, neurogenic differentiation factor (NeuroD) family, achaete-scute complex-like (ASCL) family, Fer3-like protein (FERD3L)-like family, and Oligodendrocyte lineage genes (OLIG) family of transcription factors.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 2073702980  90 RMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11390     1 RNAANARERRRMHDLNDAFEALRKVLPTVPPDKKLSKIETLRLAINYIAALSDLL 55

basic helix-loop-helix (bHLH) domain found in neurogenin-2 (NGN-2) and similar proteins; NGN-2, also termed Class A basic helix-loop-helix protein 8 (bHLHa8), or protein atonal homolog 4 (ATOH4), is a neural-specific bHLH transcription factor required for sensory neurogenesis. It activates transcription by binding to the E box (5'-CANNTG-3').

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  87 KLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILSTG 147
Cdd:cd19717     8 KTRRVKANNRERNRMHNLNAALDSLREVLPTFPEDAKLTKIETLRFAHNYIWALSETLRLA 68

basic helix-loop-helix (bHLH) domain found in neurogenin-1 (NGN-1) and similar proteins; NGN-1, also termed Class A basic helix-loop-helix protein 6 (bHLHa6), or neurogenic basic-helix-loop-helix protein, or neurogenic differentiation factor 3 (NeuroD3), is a neural-specific bHLH transcription factor involved in the initiation of neuronal differentiation. It activates transcription by binding to the E box (5'-CANNTG-3').

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 2073702980  87 KLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19716    15 KSRRVKANDRERNRMHNLNAALDELRSVLPSFPDDTKLTKIETLRFAHNYIWALSETL 72

basic helix-loop-helix (bHLH) domain found in protein atonal homologs ATOH1, ATOH7 and similar proteins; The family includes ATOH1 and ATOH7. ATOH1, also termed Class A basic helix-loop-helix protein 14 (bHLHa14), or helix-loop-helix protein hATH-1 (hATH1), or Math1, or Cath1, is a proneural bHLH transcription factor that is essential for inner ear hair cell differentiation. It dimerizes with E47 and activates E-box (CANNTG) dependent transcription. ATOH1 is a mammalian homolog of the Drosophila melanogaster gene atonal and mouse atonal homolog 1 (Math1). ATOH7, also termed Class A basic helix-loop-helix protein 13 (bHLHa13), or helix-loop-helix protein hATH-5 (hATH5), or Math5, is a bHLH transcription factor involved in the differentiation of retinal ganglion cells. The family also includes protein Amos (also termed absent MD neurons and olfactory sensilla protein, or reduced olfactory organs protein, or rough eye protein). It is a bHLH transcription factor that promotes multiple dendritic neuron formation in the Drosophila peripheral nervous system.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11430     1 RRLAANARERRRMNGLNRAFDQLRSVVPSIGNDKKLSKYETLQMAQIYIETLSELL 56

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 1 (ATOH1) and similar proteins; ATOH1, also termed Class A basic helix-loop-helix protein 14 (bHLHa14), or helix-loop-helix protein hATH-1 (hATH1), or Math1, or Cath1, is a proneural bHLH transcription factor that is essential for inner ear hair cell differentiation. It dimerizes with E47 and activates E-box (CANNTG) dependent transcription. ATOH1 is a mammalian homolog of the Drosophila melanogaster gene atonal and mouse atonal homolog 1 (Math1).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980  87 KLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILST 146
Cdd:cd19713     4 KQRRLAANARERRRMHGLNHAFDQLRNVIPSFNNDKKLSKYETLQMAQIYINALSELLQG 63

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster protein Amos and similar proteins; Amos, also termed absent MD neurons and olfactory sensilla protein, or reduced olfactory organs protein, or rough eye protein, is a bHLH transcription factor that promotes multiple dendritic neuron formation in the Drosophila peripheral nervous system.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2073702980  84 DRVKLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILS 145
Cdd:cd19715     3 DVLKKRRLAANARERRRMNSLNVAFDKLRDVVPSLGDDRKLSKYETLQMAQSYITALKELLS 64

Helix-loop-helix DNA-binding domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYI 137
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYI 49

basic helix-loop-helix (bHLH) domain found in muscle, intestine and stomach expression 1 (MIST-1) family; MIST-1, also termed Class A basic helix-loop-helix protein 15 (bHLHa15), or Class B basic helix-loop-helix protein 8 (bHLHb8), is a bHLH transcription factor expressed in pancreatic acinar cells and other serous exocrine cells. It is essential for cytoskeletal organization and secretory activity. It also functions as a potent endoplasmic reticulum (ER) stress-inducible transcriptional regulator. MIST-1 is capable of binding to E-box (CANNTG) motifs as a homodimer or a heterodimer with E-proteins (E12 and E47) to regulate transcription. The family also includes Drosophila melanogaster protein dimmed and similar proteins. Dimmed, also termed DIMM, is a bHLH transcription factor that regulates neurosecretory (NS) cell function and neuroendocrine cell fate in Drosophila.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11426     1 RRLESNERERLRMHQLNDAFQALREVIPHVRSERKLSKIETLTLAKNYIKSLTNMI 56

basic helix-loop-helix (bHLH) domain found in Oligodendrocyte lineage genes (OLIG) family of transcription factors; The OLIG family includes three bHLH transcription factors, Oligo1-3, which are expressed in both the developing and mature central nervous system. Oligo1 and Oligo2 are expressed in a nervous tissue-specific manner, but Oligo3 is found mainly in non-neural tissues. Oligo (also known as Olig) have key roles in the specification of motor neurons, dorsal interneurons, and oligodendrocytes. Oligo1, also termed Class B basic helix-loop-helix protein 6 (bHLHb6), or Class E basic helix-loop-helix protein 21 (bHLHe21), promotes formation and maturation of oligodendrocytes, especially within the brain. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons. This family also includes two OLIG-related bHLH transcription factors, bHLHe22 and bHLHe23. bHLHe22, also termed Class B basic helix-loop-helix protein 5 (bHLHb5), or trinucleotide repeat-containing gene 20 protein, is a neural-specific transcriptional repressor that is expressed in both excitatory (unipolar brush cells) and inhibitory neurons (cartwheel cells) of the dorsal cochlear nucleus (DCN) during development. It is important for the proper development and/or survival of a number of neural cell types. bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 2073702980  90 RMEANARERNRMHGLNNALDSLRKVVPCY--SKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11429     1 RLKINSRERKRMHDLNSALDGLRSVMPYAqgPSVRKLSKIATLLLARNYILMLTQAL 57

basic helix-loop-helix (bHLH) domain found in scleraxis, transcription factor 15 (TCF-15) and similar proteins; The family includes scleraxis and transcription factor 15 (TCF-15). Scleraxis, also termed SCX, or Class A basic helix-loop-helix protein 41 (bHLHa41), or Class A basic helix-loop-helix protein 48 (bHLHa48), is a bHLH transcription factor that is expressed in sclerotome limb bud cranial and body wall mesenchyme, pericardium and heart valves, ligaments and tendons. It is required for tendon formation ligaments, connective tissue, the diaphragm, and testis development. Scleraxis plays a central role in promoting fibroblast proliferation and matrix synthesis during the embryonic development of tendons. TCF-15, also termed Class A basic helix-loop-helix protein 40 (bHLHa40), or paraxis, or protein bHLH-EC2, is a bHLH transcription factor expressed in caudal lateral and paraxial mesoderm dermomyotome and sclerotome fore limb buds during embryo development. It may function as an early transcriptional regulator involved in the patterning of the mesoderm and in lineage determination of cell types derived from the mesoderm.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 2073702980  90 RMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11465     1 RQAANARERDRTHSVNSAFTALRTLIPTEPADRKLSKIETLRLASSYISHLATVL 55

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factors, Oligo2, Oligo3 and similar proteins; The family includes two bHLH transcription factors, Oligo2 and Oligo3. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2073702980  90 RMEANARERNRMHGLNNALDSLRKVVPcYSK---TQKLSKIETLRLAKNYIWALSEILSTGKR 149
Cdd:cd19725     2 RLKINSRERKRMHDLNSALDGLREVMP-YAHgpsVRKLSKIATLLLARNYILMLTNSLEEMKR 63

basic helix-loop-helix (bHLH) domain found in achaete-scute complex-like (ASCL) family; The achaete-scute complex-like (ASCL, also known as achaete-scute complex homolog or ASH) family of bHLH transcription factors, ASCL1-5, have been implicated in cell fate specification and differentiation. They are critical for proper development of the nervous system. The deregulation of ASCL plays a key role in psychiatric and neurological disorders. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete-scute homolog 1 (Mash1), is a neural-specific bHLH transcription factor that is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete-scute homolog 2 (Mash2), is a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is a bHLH transcription factor specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. The family also includes Drosophila melanogaster achaete-scute complex (AS-C) proteins, which consists of lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 2073702980  87 KLRRmeaNARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11418     2 VARR---NERERRRVQAVNDAFDRLRQHVPYLKRRKKLSKVKTLRRAIEYIRHLQKLL 56

basic helix-loop-helix (bHLH) domain found in Caenorhabditis elegans Helix-loop-helix protein 13 (HLH13) and similar proteins; Caenorhabditis elegans HLH13, also termed Fer3-like protein, or nephew of atonal 3, is a bHLH transcription factor that plays a role in the negative regulation of exit from L1 arrest and dauer diapause dependent on IIS signaling (insulin and insulin-like growth factor (IGF) signaling).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  87 KLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILSTG 147
Cdd:cd11416     3 KVQRHAANIRERKRMLSINSAFEELRCHVPTFPYEKRLSKIDTLRLAIAYIALLRDILRSG 63

basic helix-loop-helix (bHLH) domain found in twist-related protein (TWIST) family; The TWIST family includes TWIST1 and TWIST2, which are highly homologous bHLH transcription factors that promote epithelial-mesenchymal transition (EMT) during development and tumor metastasis. They are involved in the negative regulation of cellular determination and in the differentiation of several lineages, including myogenesis, osteogenesis, and neurogenesis. TWIST factors express in broad partially-overlapping patterns during embryo development and dimerize with a broad sets of dimer partners that form numerous unique transcriptional complexes to regulate embryonic development.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSkTQKLSKIETLRLAKNYIWALSEILSTG 147
Cdd:cd11464     1 QRVLANVRERQRTQSLNEAFTSLRKIIPTLP-SDKLSKIQTLKLAARYIDFLYQVLRSD 58

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster achaete-scute complex (AS-C) proteins, achaete-scute-like proteins, ASCL1-2, and similar proteins; This subfamily includes Drosophila melanogaster AS-C proteins and two ASCL family of transcription factors, ASCL-1 and ASCL-2. Drosophila melanogaster AS-C proteins includes lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete scute homolog 1 (Mash1), is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  94 NARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19723     6 NERERNRVKLVNLGFATLREHVPNGRANKKMSKVETLRSAVEYIRQLQQLL 56

basic helix-loop-helix (bHLH) domain found in pancreas transcription factor 1 subunit alpha (PTF1A) and similar proteins; PTF1A, also termed Class A basic helix-loop-helix protein 29 (bHLHa29), or pancreas-specific transcription factor 1a, or bHLH transcription factor p48, or p48 DNA-binding subunit of transcription factor PTF1 (PTF1-p48), is a bHLH transcription factor implicated in the cell fate determination in various organs. It binds to the E-box consensus sequence 5'-CANNTG-3' and plays a role in early and late pancreas development and differentiation.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11417     1 QRQAANLRERRRMQSINDAFEGLRSHIPTLPYEKRLSKVDTLRLAIGYINFLSELV 56

basic helix-loop-helix (bHLH) domain found in twist-related protein 1 (TWIST1) and similar proteins; TWIST1, also termed Class A basic helix-loop-helix protein 38 (bHLHa38), or H-twist, is a bHLH transcriptional regulator that inhibits myogenesis by sequestrating E proteins, inhibiting trans-activation by MEF2, and inhibiting DNA-binding by MYOD1 through physical interaction. It also represses expression of proinflammatory cytokines such as TNFA and IL1B. In addition, TWIST1 is involved in cancer development and progression.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2073702980  84 DRVKLRRMEANARERNRMHGLNNALDSLRKVVPCYSkTQKLSKIETLRLAKNYIWALSEILST 146
Cdd:cd11412     7 EELQTQRVMANVRERQRTQSLNEAFAALRKIIPTLP-SDKLSKIQTLKLAARYIDFLYQVLQS 68

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factor 1 (Oligo1) and similar proteins; Oligo1, also termed Class B basic helix-loop-helix protein 6 (bHLHb6), or Class E basic helix-loop-helix protein 21 (bHLHe21), is a bHLH transcription factor that promotes formation and maturation of oligodendrocytes, especially within the brain.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2073702980  87 KLRRmEANARERNRMHGLNNALDSLRKVVPCYSKT-------QKLSKIETLRLAKNYIWALSEILSTGKR 149
Cdd:cd18942     5 QLRR-KINSRERKRMQDLNLAMDALREVILPYSAAhcqsspgRKLSKIATLLLARNYILLLGSSLQELRR 73

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factor 2 (Oligo2) and similar proteins; Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is a bHLH transcription factor that is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2073702980  75 KKKMTKARVDRVklrRMEANARERNRMHGLNNALDSLRKVVPcYS---KTQKLSKIETLRLAKNYIWALSEILSTGKR 149
Cdd:cd18940     4 KKQMSEPELQQL---RLKINSRERKRMHDLNIAMDGLREVMP-YAhgpSVRKLSKIATLLLARNYILMLTNSLEEMKR 77

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein (HAND) family; The HAND family includes two bHLH transcription factors, HAND1 and HAND2. HAND1, also termed Class A basic helix-loop-helix protein 27 (bHLHa27), or extraembryonic tissues, heart, autonomic nervous system and neural crest derivatives-expressed protein 1 (eHAND), plays an essential role in both trophoblast-giant cells differentiation and in cardiac morphogenesis. HAND2, also termed Class A basic helix-loop-helix protein 26 (bHLHa26), or deciduum, heart, autonomic nervous system and neural crest derivatives-expressed protein 2 (dHAND), is essential for cardiac morphogenesis, particularly for the formation of the right ventricle and of the aortic arch arteries.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd11466     1 RRGSANKKERRRTQSINSAFADLRECIPNVPADTKLSKIKTLRLATSYIAYLMDVL 56

basic Helix Loop Helix (bHLH) domain superfamily; bHLH proteins are transcriptional regulators that are found in organisms from yeast to humans. Members of the bHLH superfamily have two highly conserved and functionally distinct regions. The basic part is at the amino end of the bHLH that may bind DNA to a consensus hexanucleotide sequence known as the E box (CANNTG). Different families of bHLH proteins recognize different E-box consensus sequences. At the carboxyl-terminal end of the region is the HLH region that interacts with other proteins to form homo- and heterodimers. bHLH proteins function as a diverse set of regulatory factors because they recognize different DNA sequences and dimerize with different proteins. The bHLH proteins can be divided to cell-type specific and widely expressed proteins. The cell-type specific members of bHLH superfamily are involved in cell-fate determination and act in neurogenesis, cardiogenesis, myogenesis, and hematopoiesis.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 2073702980  97 ERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSE 142
Cdd:cd00083     1 ERRRRDKINDAFEELKRLLPELPDSKKLSKASILQKAVEYIRELQS 46

basic helix-loop-helix (bHLH) domain found in Class A basic helix-loop-helix protein 9 (bHLHa9) and similar proteins; bHLHa9, also termed Class F basic helix-loop-helix factor 42 (bHLHf42), is a bHLH transcription factor that plays an essential role in limb development.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2073702980  82 RVDRVKLRRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd18912     1 RPVRSKARRVAANVRERKRILDYNQAFNALRLALKHDLGGKRLSKIATLRRAINRISALSLFL 63

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster achaete-scute complex (AS-C) proteins and similar proteins; Drosophila melanogaster AS-C proteins includes lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2073702980  94 NARERNRMHGLNNALDSLRKVVPCY-----------SKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19744     6 NARERNRVKQVNNGFAILRQHIPQSviedltagggrGKSKKLSKVDTLRMAVEYIRRLQKLL 67

basic helix-loop-helix (bHLH) domain found in mesogenin-1 (Msgn1) and similar proteins; Msgn1, also termed paraxial mesoderm-specific mesogenin1, or pMesogenin1 (pMsgn1), is a bHLH transcription factor required for maturation and segmentation of paraxial mesoderm. It may regulate the expression of T-box transcription factors essential for mesoderm formation and differentiation.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVV-PCYSKT-QKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd18939     8 RRRKASEREKLRMRTLAEALHTLRNYLpPVYSQRgQPLTKIQTLKCTIQYISELSGLL 65

basic helix-loop-helix (bHLH) domain found in achaete-scute-like proteins, ASCL3-5, and similar proteins; This subfamily includes three ASCL family of transcription factors, ASCL-3, ASCL-4 and ASCL-5. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, may be involved in skin development. ASCL-5, also termed Class A basic helix-loop-helix protein 47 (bHLHa47), or achaete-scute homolog 5 (ASH-5), is an uncharacterized bHLH transcription factor that is close related to ASCL-3 and ASCL-4.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  94 NARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19724     6 NERERQRVRCVNEGYARLRRHLPLENKDKRLSKVETLRAAIRYIKHLQELL 56

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 2 (ASCL-2) and similar proteins; ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  94 NARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19743     8 NERERNRVKLVNLGFAALRQHVPQGGASKKMSKVETLRSAVEYIRALQRLL 58

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein 1 (HAND1) and similar proteins; HAND1, also termed Class A basic helix-loop-helix protein 27 (bHLHa27), or extraembryonic tissues, heart, autonomic nervous system and neural crest derivatives-expressed protein 1 (eHAND), is a bHLH transcription factor that plays an essential role in both trophoblast-giant cells differentiation and in cardiac morphogenesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILS 145
Cdd:cd18952     2 RKGAGPKKERRRTESINSAFAELRECIPNVPADTKLSKIKTLRLATSYIAYLMDVLA 58

basic helix-loop-helix (bHLH) domain found in protein lyl-1 and similar proteins; Lyl-1, also termed Class A basic helix-loop-helix protein 18 (bHLHa18), or lymphoblastic leukemia-derived sequence 1, is a proto-oncogenic bHLH transcription factor involved in T-cell acute lymphoblastic leukemia. It plays an important role in hematopoietic stem cell function and is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. LYL-1 deficiency induces a stress erythropoiesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19705     6 RRVFTNSRERWRQQNVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYIDFLVTLL 61

basic helix-loop-helix (bHLH) domain found in the mesoderm posterior protein (Mesp) family; Mesp, a bHLH tissue specific transcription factor, acts as a key regulator of the cardiovascular transcriptional network by inducing directly and/or indirectly the expression of the majority of key cardiovascular transcription factors. The Mesp family includes two bHLH transcription factors, Mesp1 and Mesp2. Mesp1, also termed Class C basic helix-loop-helix protein 5 (bHLHc5), promotes cardiovascular differentiation during embryonic development and embryonic stem cell differentiation. Mesp2, also termed Class C basic helix-loop-helix protein 6 (bHLHc6), plays an important role in somitogenesis.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVP--CYSKTQKLSKIETLRLAKNYIWALSEILSTGKRP 150
Cdd:cd18938     1 QRQSASEREKLRMRDLAKALHNLRRYLPpsVAPAGQSLTKIETLRLTIRYISHLSAQLGLSEES 64

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in transcription factor AP-4 (TFAP4) and similar proteins; TFAP4, also termed activating enhancer-binding protein 4, or Class C basic helix-loop-helix protein 41 (bHLHc41), is a bHLHzip transcription factor that activates both viral and cellular genes involved in the regulation of cellular proliferation, stemness, and epithelial-mesenchymal transition by binding to the symmetrical DNA sequence 5'-CAGCTG-3'.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2073702980  87 KLRRMEANARERNRMHGLNNALDSLRKVVPCYSKtQKLSKIETLRLAKNYIWAL 140
Cdd:cd11419     2 RIRREIANSNERRRMQSINAGFQSLRTLLPHCDG-EKLSKAAILQQTAEYIFSL 54

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster myogenic-determination protein (dMYOD) and similar proteins; dMYOD, also termed protein nautilus, or Myd, may play an important role in the early development of muscle in Drosophila.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVpCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19699     2 RRKAATMRERRRLRKVNEAFEVLKRRT-CPNPNQRLPKVEILRNAIEYIESLEDLL 56

basic helix-loop-helix (bHLH) domain found in transcription factor 23 (TCF-23) and similar proteins; TCF-23, also termed Class A basic helix-loop-helix protein 24 (bHLHa24), is a bHLH transcription factor that is essential for progesterone-dependent decidualization. The mouse homolog is also called ovary, uterus and testis protein (OUT), which is expressed predominantly in the reproductive organs such as the uterus, ovary and testis. It shows an Id-like inhibitory activity and functions as a negative regulator of bHLH factors through the formation of a functionally inactive heterodimeric complex. OUT inhibits the formation of TCF3 and MYOD1 homodimers and heterodimers, but lacks DNA binding activity. OUT is involved in the regulation or modulation of smooth muscle contraction of the uterus during pregnancy and particularly around the time of delivery. It also plays a role in the inhibition of myogenesis. Unlike typical bHLH factors, OUT proteins do not bind E-box (CANNTG) or N-box DNA sequences and inhibit DNA binding of homo- and heterodimers consisting of E12 and MyoD in gel mobility shift assays.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 2073702980  92 EANARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19709     3 ENAARERSRVRTLRQAFLALQAALPSVPPDTKLSKLDVLVLATSYIAHLTRTL 55

basic helix-loop-helix (bHLH) domain found in helix-loop-helix protein 2 (HEN-2) and similar proteins; HEN-2, also termed nescient helix-loop-helix 2 (Nhlh2), or Class A basic helix-loop-helix protein 34 (bHLHa34), or nescient helix loop helix 2 (NSCL-2), is a neuron-specific bHLH transcription factor that may serve as DNA-binding protein and may be involved in the control of cell-type determination, possibly within the developing nervous system.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  80 KARVDRVKLRRMEANA-RERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19702     6 KRRRRRATAKYRSAHAtRERIRVEAFNLAFAELRKLLPTLPPDKKLSKIEILRLAICYISYLNHVL 71

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 5 (ASCL-5) and similar proteins; ASCL-5, also termed Class A basic helix-loop-helix protein 47 (bHLHa47), or achaete-scute homolog 5 (ASH-5), is an uncharacterized bHLH transcription factor that belongs to AS-C (achaete, scute, lethal of scute, and asense) family.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  94 NARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19747    11 NERERQRVKCVNEGYARLRDHLPGAMAEKRLSKVETLRAAIRYIKYLQDLL 61

basic helix-loop-helix (bHLH) domain found in myogenin (MYOG) and similar proteins; MYOG, also termed Class C basic helix-loop-helix protein 3 (bHLHc3), or myogenic factor 4 (Myf-4), is a bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle differentiation, cell cycle exit and muscle atrophy.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVpCYSKTQKLSKIETLRLAKNYIWALSEILST 146
Cdd:cd18935     2 RRRAATLREKRRLKKVNEAFEALKRST-LLNPNQRLPKVEILRSAIQYIERLQALLSS 58

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 3 (ASCL-3) and similar proteins; ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is a bHLH transcription factor specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 2073702980  94 NARERNRMHGLNNALDSLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd19745     9 NERERQRVKCVNEGYAKLRRHLPQEYSEKRLSKVETLRAAIKYIKHLQSVL 59

basic helix-loop-helix (bHLH) domain found in myoblast determination protein 1 (MYOD1) and similar proteins; MYOD1, also termed Class C basic helix-loop-helix protein 1 (bHLHc1), or myogenic factor 3 (Myf-3), is a bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle differentiation. Together with Myf-5 and MYOG, MYOD1 co-occupies muscle-specific gene promoter core region during myogenesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2073702980  89 RRMEANARERNRMHGLNNALDSLRKVVPCySKTQKLSKIETLRLAKNYIWALSEIL 144
Cdd:cd18936     6 RRKAATMRERRRLSKVNEAFETLKRCTST-NPNQRLPKVEILRNAIRYIESLQALL 60

basic helix-loop-helix (bHLH) domain found in Arabidopsis thaliana protein aborted microspores (AMS) and similar proteins; The family includes several bHLH transcription factors from Arabidopsis thaliana, such as AMS, ICE1 and SCREAM2. AMS, also termed AtbHLH21, or EN 48, plays a crucial role in tapetum development and it is required for male fertility and pollen differentiation. ICE1, also termed inducer of CBF expression 1, or AtbHLH116, or EN 45, or SCREAM, acts as a transcriptional activator that regulates the cold-induced transcription of CBF/DREB1 genes. It binds specifically to the MYC recognition sites (5'-CANNTG-3') found in the CBF3/DREB1A promoter. SCREAM2, also termed AtbHLH33, or EN 44, mediates stomatal differentiation in the epidermis probably by controlling successive roles of SPCH, MUTE, and FAMA.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 2073702980  97 ERNRMHGLNNALDSLRKVVPcysKTQKLSKIETLRLAKNYI 137
Cdd:cd11443     7 ERRRRKKLNDRLYMLRSVVP---KITKMDRASILGDAIDYV 44