HB2 hemoglobin 2 [Arabidopsis thaliana (thale cress)] - Gene

Summary

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Official Symbol: HB2
Official Full Name: hemoglobin 2
Primary source: TAIR:AT3G10520
Locus tag: AT3G10520
See related: Araport:AT3G10520
Gene type: protein coding
RefSeq status: REVIEWED
Organism: Arabidopsis thaliana (ecotype: Columbia)
Lineage: Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis
Also known as: AHB2; ARABIDOPSIS HEMOGLOBIN 2; ARATH GLB2; ATGLB2; GLB2; haemoglobin 2; HEMOGLOBIN; HEMOGLOBIN 2; NON-SYMBIOTIC HAEMOGLOBIN 2; NSHB2
Summary: Encodes a class 2 non-symbiotic hemoglobin. Over-expression of AHb2 in seeds led to a 40% increase in the total fatty acid content of developing and mature seeds in three subsequent generations. This was mainly due to an increase in the poly-unsaturated C18:2 (omega-6) linoleic and C18:3 (omega-3) alpha-linolenic acids.
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Genomic context

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See HB2 in Genome Data Viewer

Location:: chromosome: 3

Exon count:: 4

Sequence:: Chromosome: 3; NC_003074.8 (3276163..3277930, complement)

Chromosome 3 - NC_003074.8 Genomic Context describing neighboring genes

Genomic regions, transcripts, and products

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Go to reference sequence details

Genomic Sequence:: NC_003074.8

Go to nucleotide: Graphics FASTA GenBank

Bibliography

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GeneRIFs: Gene References Into Functions

What's a GeneRIF?

Data suggest that Glbs modulate nitric oxide (NO) and interact with abscisic acid (ABA) in crucial physiological processes such as the plant's response to dessication.
Title: Phytoglobins in the nuclei, cytoplasm and chloroplasts modulate nitric oxide signaling and interact with abscisic acid.
The results of this study collectively suggest that the presence of Pgb2 in the cytoplasm, but not in the nucleus, phenocopies the effects of Pgb2 mutation in inducing somatic embryogenesis.[Pgb2]
Title: Cellular localization of the Arabidopsis class 2 phytoglobin influences somatic embryogenesis.
data fit a model integrating JA in the PGB2 regulation of Arabidopsis embryogenesis. Suppression of PGB2 increases JA through nitric oxide.[PGB2]
Title: Jasmonic acid is a downstream component in the modulation of somatic embryogenesis by Arabidopsis Class 2 phytoglobin.
GLB2 pays a role in mediating somatic embryogenesis, and is a potential modulator of auxin synthesis and transport.
Title: Function of type-2 Arabidopsis hemoglobin in the auxin-mediated formation of embryogenic cells during morphogenesis.
The production of both Nitric oxide (NO) and ethylene gases was increased with reduced expression of either of the Hb genes GLB1 or GLB2, whereas NO emission decreased in plants overexpressing these genes.
Title: Haemoglobin modulates NO emission and hyponasty under hypoxia-related stress in Arabidopsis thaliana.
Over-expression of GLB1 and GLB2 induces shoot formation at low levels of cytokinins.
Title: Manipulation of hemoglobin expression affects Arabidopsis shoot organogenesis.
Results are consistent with a role for AHb2 as an oxygen carrier, as recently proposed on the basis of experiments on AHb2-overexpressing mutants of A. thaliana.
Title: Oxygen binding to Arabidopsis thaliana AHb2 nonsymbiotic hemoglobin: evidence for a role in oxygen transport.
These results provide evidence for a specific function of class 2 hemoglobin in seed oil production and in promoting the accumulation of polyunsaturated fatty acids by facilitating oxygen supply in developing seeds.
Title: Nonsymbiotic hemoglobin-2 leads to an elevated energy state and to a combined increase in polyunsaturated fatty acids and total oil content when overexpressed in developing seeds of transgenic Arabidopsis plants.
In AHb2, the HisE7 side chain is removed from the bound ligand; rebinding barriers are low, and CO molecules can populate only primary docking site B.
Title: Ligand migration and binding in nonsymbiotic hemoglobins of Arabidopsis thaliana.
Finding strongly supports the idea that AHb1 and AHb2 have distinct physiological functions.
Title: Different roles of protein dynamics and ligand migration in non-symbiotic hemoglobins AHb1 and AHb2 from Arabidopsis thaliana.

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General gene information

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NM_111887.3

Supported by ESTs:

Gene Ontology Provided by TAIR

Function	Evidence Code	Pubs
enables heme binding	IEA Inferred from Electronic Annotation more info
enables oxygen binding	IEA Inferred from Electronic Annotation more info
enables oxygen carrier activity	ISS Inferred from Sequence or Structural Similarity more info	PubMed

Process	Evidence Code	Pubs
acts_upstream_of_or_within fatty acid metabolic process	IMP Inferred from Mutant Phenotype more info	PubMed
acts_upstream_of_or_within oxygen transport	ISS Inferred from Sequence or Structural Similarity more info	PubMed
acts_upstream_of_or_within response to cytokinin	IEP Inferred from Expression Pattern more info
acts_upstream_of_or_within triglyceride biosynthetic process	IMP Inferred from Mutant Phenotype more info	PubMed

Component	Evidence Code	Pubs
located_in cytoplasm	ISM Inferred from Sequence Model more info
located_in cytosol	HDA more info	PubMed

General protein information

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Preferred Names: hemoglobin 2

NP_187663.1

haemoglobin 2 (HB2); FUNCTIONS IN: oxygen transporter activity; INVOLVED IN: response to cytokinin stimulus; LOCATED IN: cellular_component unknown; EXPRESSED IN: 21 plant structures; EXPRESSED DURING: 13 growth stages; CONTAINS InterPro DOMAIN/s: Leghaemoglobin (InterPro:IPR001032), Globin-like (InterPro:IPR009050), Leghaemoglobin, iron-binding site (InterPro:IPR019824), Globin, subset (InterPro:IPR000971), Globin (InterPro:IPR012292); BEST Arabidopsis thaliana protein match is: hemoglobin 1 (TAIR:AT2G16060.1); Has 878 Blast hits to 840 proteins in 285 species: Archae - 0; Bacteria - 313; Metazoa - 196; Fungi - 34; Plants - 318; Viruses - 0; Other Eukaryotes - 17 (source: NCBI BLink).

NCBI Reference Sequences (RefSeq)

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Genome Annotation

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference assembly

Genomic

NC_003074.8 Reference assembly

Range

3276163..3277930 complement

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GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

NM_111887.3 → NP_187663.1 hemoglobin 2 [Arabidopsis thaliana]

See identical proteins and their annotated locations for NP_187663.1

Status: REVIEWED

UniProtKB/Swiss-Prot

O24521

UniProtKB/TrEMBL

A0A178VG78, A0A384LCX8, A0A5S9XAW8, Q0IGL1

Conserved Domains (1) summary

cd08923
Location:6 → 152

class1-2_nsHbs_Lbs; Class1 nonsymbiotic hemoglobins (nsHbs), class II nsHbs, leghemoglobins (Lbs,) and related proteins