Genetics and Breeding Center for Blunt Snout Bream, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China.
Genetics and Breeding Center for Blunt Snout Bream, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China.
Biochem Biophys Res Commun. 2018 Jun 2;500(2):443-449. doi: 10.1016/j.bbrc.2018.04.099. Epub 2018 Apr 19.
Although hypoxia-inducible factor (HIF) 1α and 2α function as master regulators of the transcriptional response to hypoxia, the function of HIF3α and its responses to hypoxic stress remain unclear in teleost fish. Here, we characterized the HIF3α cDNA in hypoxia-sensitive blunt snout bream (Megalobrama amblycephala), with 3059 bp length, consisting of an open reading frame (ORF) encoding 643 amino acid residues. Blunt snout bream HIF3α mRNA was stably expressed during stages of embryonic development and in adult tissues. After a 4 h hypoxia stress, HIF3α mRNA of the juvenile fish was significantly upregulated in the liver, brain, and kidney, and restored to the pretreatment levels after a 24 h recovery. When tagged with enhanced green fluorescent protein (EGFP) and transfected into cultured HeLa cells, blunt snout bream HIF3α was mainly distributed in the nucleus under normoxia. Treatment of the cells with CoCl to mimic hypoxic conditions showed that there was no effect about the nuclear localization of HIF3α but a statistically significant increase in HIF3α protein levels. A nuclear localization signal (NLS) sequence at the C-terminus of HIF3α may exert positive effects in the process of nuclear localization. These results suggest that blunt snout bream HIF3α could be involved in different physiological functions under normoxia and hypoxia conditions.
虽然缺氧诱导因子（HIF）1α和 2α作为缺氧转录反应的主要调节剂，但在硬骨鱼类中，HIF3α 的功能及其对低氧胁迫的反应仍不清楚。在这里，我们在对低氧敏感的团头鲂（Megalobrama amblycephala）中对 HIF3α cDNA 进行了特征描述，其 cDNA 长度为 3059bp，包含一个开放阅读框（ORF），编码 643 个氨基酸残基。团头鲂 HIF3α mRNA 在胚胎发育阶段和成年组织中稳定表达。在 4 小时的低氧应激后，幼鱼肝脏、大脑和肾脏中的 HIF3α mRNA 显著上调，并在 24 小时恢复后恢复到预处理水平。当与增强型绿色荧光蛋白（EGFP）标记并转染到培养的 HeLa 细胞中时，团头鲂 HIF3α 在常氧条件下主要分布在核内。用 CoCl 处理细胞以模拟低氧条件表明，HIF3α 的核定位没有影响，但 HIF3α 蛋白水平有统计学意义的增加。HIF3α 羧基末端的核定位信号（NLS）序列可能在核定位过程中发挥积极作用。这些结果表明，团头鲂 HIF3α 可能在常氧和低氧条件下参与不同的生理功能。
