Cloning, characterization, hypoxia and heat shock response of hypoxia inducible factor-1 (HIF-1) from the small abalone Haliotis diversicolor

Abstract

In this study, hypoxia inducible factor-1α (HIF-1α) and hypoxia inducible factor-1β (HIF-1β) from small abalone Haliotis diversicolor were cloned. The cDNA of H. diversicolor HIF-1α (HdHIF-1α) is 2,833 bp encoding a protein of 711aa and H. diversicolor HIF-1β (HdHIF-1β) is 1919 bp encoding a protein of 590aa. Similar to other species' HIF-1, HdHIF-1 has one basic helix-loop-helix (bHLH) domain and two Per-Arnt-Sim (PAS) domains, and HdHIF-1α has a oxygen-dependent degradation domain (ODDD) with two proline hydroxylation motifs and a C-terminal transactivation domain (C-TAD) with an asparagine hydroxylation motif. Under normoxic conditions, HdHIF-1α and HdHIF-1β mRNAs were constitutively present in all examined tissues. Under hypoxia (2.0mg/L DO at 25°C) stress, HdHIF-1α expression was up-regulated in gills at 4h, 24h and 96 h, and in hemocytes at 24h and 96 h, while HdHIF-1β remained relatively constant. Under thermal stress (31°C), HdHIF-1α expression was significantly increased in gills at 4h, and hemocytes at 0 h and 4 h, while HdHIF-1β expression still remained relatively constant. These results suggested that HIF-1α may play an important role in adaption to poor environment in H. diversicolor.

Keywords: ARNT; C-TAD; C-terminal transactivation domain; CBP; CREB1-binding protein; DO; Gene expression; HIF-1α; HIF-1β; HRE; Haliotis diversicolor; Hypoxia; N-TAD; N-terminal transactivation domain; NRR; NRU; ODDD; ORF; PHDs; Pro; RACE; THC; Thermal stress; UTR; aryl hydrocarbon receptor nuclear translocator; bHLH/PAS; basic helix–loop–helix/Per-Arnt-Sim; dissolved oxygen; hemocyte count; hypoxia inducible factor-1α; hypoxia inducible factor-1β; hypoxia response element; neutral red retention; neutral red uptake; open reading frame; oxygen dependent degradation domain; pVHL; proline; proline hydroxylases; qRT-PCR; quantitative real-time PCR; rapid amplification of cDNA ends; untranslated region; von Hippel–Lindau protein.