Sathyamoorthy Akila, Chaurasia Mukesh Kumar, Arasu Mariadhas Valan, Al-Dhabi Naif Abdullah, Harikrishnan Ramasamy, Arockiaraj Jesu
Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India; Department of Biotechnology, SRM Arts & Science College, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
Fish Shellfish Immunol. 2017 Jan;60:129-140. doi: 10.1016/j.fsi.2016.11.046. Epub 2016 Nov 20.
Heat shock proteins (HSPs) are immunogenic, ubiquitous class of molecular chaperones, which are induced in response to various environmental and microbial stressful conditions. It plays a vital role in maintaining cellular protein homeostasis in eukaryotic cells. In this study, we described a comprehensive comparative data by bioinformatics approach on three different full length cDNA sequences of HSP family at molecular level. The cDNA sequences of three HSPs were identified from constructed cDNA library of Channa striatus and named as CsCPN60, CsHSP60 and CsHSP70. We have conducted various physicochemical study, which showed that CsHSP70 (666 amino acid) possessed a larger polypeptides followed by CsCPN60 (575) and CsCPN60 (542). Three dimensional structural analysis of these HSPs showed maximum residues in α-helices and least in β-sheets; also CsHSP60 lacks β-sheet and formed helix-turn-helix structure. Further analysis indicated that each HSP carried distinct domains and gene specific signature motif, which showed that each HSP are structurally diverse. Homology and phylogenetic study showed that the sequences taken for analysis shared maximum identity with fish HSP family. Tissue specific mRNA expression analysis revealed that all the HSPs showed maximum expression in one of the major immune organ such as CsCPN60 in kidney, CsHSP60 in spleen and CsHSP70 in head kidney. To understand the function of HSPs in murrel immune system, the elevation in mRNA expression level was analyzed against microbial oxidative stressors such as fungal (Aphanomyces invadans) and bacterial (Aeromonas hydrophila). It is interesting to note that all the HSP showed a different expression pattern and reached maximum up-regulation at 48 h post-infection (p.i) during fungal stress, whereas in bacterial stress only CsCPN60 showed maximum up-regulation at 48 h p.i, but CsHSP60 and CsHSP70 showed maximum up-regulation at 24 h p.i. The differential expression pattern showed that each HSP is diverse in function. Overall, the elevation in expression levels showed that HSPs might have potential involvement in murrel immune protection thus, protecting the organism against various external stimuli including environmental and microbial stress.
热休克蛋白（HSPs）是一类具有免疫原性且普遍存在的分子伴侣，在各种环境和微生物应激条件下被诱导产生。它在维持真核细胞内蛋白质稳态方面起着至关重要的作用。在本研究中，我们通过生物信息学方法在分子水平上描述了热休克蛋白家族三种不同全长cDNA序列的全面比较数据。从构建的条纹鳢cDNA文库中鉴定出三种热休克蛋白的cDNA序列，并将其命名为CsCPN60、CsHSP60和CsHSP70。我们进行了各种理化研究，结果表明，CsHSP70（666个氨基酸）具有较大的多肽链，其次是CsCPN60（575个）和CsCPN60（542个）。对这些热休克蛋白的三维结构分析表明，α-螺旋中的残基最多，β-折叠中的残基最少；此外，CsHSP60缺乏β-折叠，形成螺旋-转角-螺旋结构。进一步分析表明，每个热休克蛋白都带有不同的结构域和基因特异性特征基序，这表明每个热休克蛋白在结构上是多样的。同源性和系统发育研究表明，用于分析的序列与鱼类热休克蛋白家族具有最高的同源性。组织特异性mRNA表达分析显示，所有热休克蛋白在主要免疫器官之一中表达最高，如CsCPN60在肾脏中，CsHSP60在脾脏中，CsHSP70在头肾中。为了了解热休克蛋白在鳢免疫系统中的功能，分析了它们在面对微生物氧化应激源如真菌（侵袭性丝囊霉菌）和细菌（嗜水气单胞菌）时mRNA表达水平的升高情况。有趣的是，所有热休克蛋白都表现出不同的表达模式，在真菌应激期间，感染后48小时（p.i）达到最大上调，而在细菌应激中，只有CsCPN60在感染后48小时表现出最大上调，但CsHSP60和CsHSP70在感染后24小时表现出最大上调。这种差异表达模式表明每个热休克蛋白的功能各不相同。总体而言，表达水平的升高表明热休克蛋白可能潜在地参与鳢的免疫保护，从而保护生物体免受包括环境和微生物应激在内的各种外部刺激。
