热休克、Poly I:C上调草鱼GRP78基因表达

葡萄糖调节蛋白78(GRP78)是细胞内一种应急蛋白,它通过对细胞内、外胁迫因子产生强烈的应答而调节内质网稳态.草鱼(Ctenopharyngodon idellus)GRP78克隆于草鱼肝肾cDNA文库,全长2 490 bp.其中,5'非编码区为155 bp,含有7个热休克元件,3'非编码区为373 bp,最大开放阅读框为1 962 bp,编码653个氨基酸.序列分析表明,草鱼GRP78的N端包含3个HSP70家族的签名序列,C末端为内质网蛋白滞留信号KDEL,草鱼GRP78与人及其它动物的同源性很高.适应性进化分析也显示GRP78非常保守,受到强烈的功能约束,说明该蛋白质在进化中非常重要.RT-PCR分析表明,相对于本底水平,34℃热激和Poly I:c诱导后,草鱼GRP78在肝、肾等组织巾的表达明显上调.图4表1参16

Up-regulation of Grass Carp GRP78 Gene Expression under Heat Shock and Poly I:C Stress

Glucose regulated protein 78 (GRP78), as a cellular stress-related protein, could regulate endoplasmic reticulum (ER) homeostasis by strongly responding to intracellular or extracellular stressors. The grass carp (Ctenopharyngodon idellus) GRP78 gene was cloned from mixed liver and kidney cDNA library. The full length sequence of 2 490 bp contained a 5' untranslated region of 155 bp with seven heat shock elements and a 3'untranslated region of 373 bp. The open reading frame was 1 962 bp which could code a 653 amino acid peptide. The deduced amino acid sequence of grass carp GRP78 contained three signature sequences of HSP70s in the N-terminus, and an endoplasmic reticulum retention sequence of KOEL in its C-terminus. The grass carp GRP78 shared the high homology with that of human and other animals. The analysis of adaptive evolution demonstrated that GRP78 was highly conservative and undergoing strong functional constraint, which illustrated it was very important in the course of evolution. The RT-PCR analysis showed that the expression of grass carp GRP78 was significantly enhanced in liver, kidney and other tissues after heat shock at 34 ℃ and challenged by Poly I:C compared with the normal level. Fig 4, Tab 1, Ref 16