Hypoxia response

The goal of the study was to identify hypoxia-induced gene expression changes in C. elegans and to determine which of these responses to hypoxia were regulated by hif-1. Towards these aims, we analyzed mRNA expression patterns in synchronized populations of wild-type worms that were cultured in standard lab conditions (normoxia) or in hypoxia. We also assayed mRNA from two mutant strains: (i) animals carrying the strong loss-of-function mutation in hif-1 and (ii) C. elegans that carry a deletion in vhl-1 and express the HIF-1 protein at constitutively high levels. In the microarray experiments, 3 strains were assayed: wild type N2, hif-1 (ia04), and vhl-1 (ok161). Worms were incubated for 4 hours in 21% oxygen or 0.1% oxygen at 210C. Animals were quickly harvested in ice cold M9 buffer, and poly (A) RNA was isolated using established procedures. No more than 3 minutes elapsed between the removal of plates from the hypoxic chamber and the addition of Trizol. RNA was isolated from three independent experiments for each experimental condition (3 genotypes; normoxia vs hypoxia). mRNAs were hybridized to whole-genome microarrays which contained probes for 17,817 predicted genes (94% of the genome). Ch1 in the array represents the data for the worms growed under hypoxia; and Ch2 in the array reprents the data for the worms growed under normoxia. Keywords: Biological Replicates Set of arrays that are part of repeated experiments