Total RNA was isolated from placental villous tissues with Trizol reagent (Invitrogen, Carlsbad, CA). RNA quality and quantity was assessed by Agilent 2100 Bioanalyzer (Agilent Technologies, Palo Alto, CA).
Label
biotin
Label protocol
Biotinylated cRNA were prepared according to the standard Affymetrix protocol from 1 ug total RNA (FlashTag Biotin HSR RNA Labeling Kit, Affymetrix).
Hybridization protocol
Following fragmentation, 1 ug of labeled product was hybridized for 18 hr at 48C on GeneChip miRNA 2.0 arrays . GeneChips were washed and stained in the Affymetrix Fluidics Station 450.
Scan protocol
GeneChips were scanned using the Affymetrix GeneChip Scanner 3000 7G.
Data processing
The data were analyzed with Expression Console 1.2, using RMA + DABG, on a linear scale.
