文摘
Hypoxia inducible factors (HIFs) are considered to be the master switch of oxygen-dependent gene expression with mammalian species. In most cases, regulation of HIF has been believed at posttranslational levels. However, little is known of HIF regulation in channel catfish, a species highly tolerant to low oxygen condition. Here we report the identification and characterization of HIF-1伪, HIF-2伪a, HIF-2伪b, HIF-3伪, and FIH-1 genes, and their mRNA expression under hypoxia conditions. The transcripts of the five genes were found to be regulated temporally and spatially after low oxygen challenge, suggesting regulation of HIF-伪 genes at pre-translational levels. In most tissues, the HIF-伪 mRNAs were down-regulated 1.5 h but up-regulated 5 h after hypoxia treatment. Of these HIF-伪 mRNAs, the expression of HIF-3伪 mRNA was induced in the most dramatic fashion, both in the speed of induction and the extent of induction, compared to HIF-1伪 and HIF-2伪 genes, suggesting its importance in responses to hypoxia.