Mohindra V, Tripathi RK, Singh RK, Lal KK. Molecular characterization and expression analysis of three hypoxia-inducible factor alpha subunits, HIF-1α, -2α and -3α in hypoxia-tolerant Indian catfish, Clarias batrachus [Linnaeus, 1758].
Mol Biol Rep 2013;
40:5805-15. [PMID:
24065526 DOI:
10.1007/s11033-013-2685-1]
[Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 09/14/2013] [Indexed: 01/01/2023]
Abstract
The present study aimed at characterization of three HIF-α subunits, HIF-1α -2α and -3α from hypoxia-tolerant Clarias batrachus, as well as to elucidate their expression pattern under short and long-term hypoxic conditions and identification of biomarker candidate. The complete cDNAs of HIF-1α, -2α and -3α were 2,833, 4,270 and 3,256 bp in length, encoding 774, 818 and 628 amino acid residues, respectively. In C. batrachus, HIF-α subunits were structurally similar in DNA binding, dimerization, degradation and transcriptional activation domains, but differed in their oxygen-dependent degradation domains. Presence of c-Jun N-terminal kinase binding domain in HIF-α subunits was reported here for the first time in fish. In adult C. batrachus, three HIF-α mRNAs were detected in different tissues under normoxic conditions, however HIF-1α was highly expressed in all the tissues studied, in comparison to HIF-2α and -3α. Short-term hypoxia exposure caused significant increase in three HIF-α transcripts in brain, liver and head kidney, while after long-term hypoxia exposure, significant up-regulation of HIF-1α in spleen and -2α in muscle was observed and HIF-3α significantly down-regulated in head kidney. These observations suggest that the differential expression of HIF-α subunits in C. batrachus was hypoxic time period dependent and may play specialized roles in adaptive response to hypoxia. HIF-2α, with its highly elevated expression in muscle tissues, can be a robust biomarker candidate for exposure to hypoxic environment.
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