花鲈Claudins基因家族的鉴定、进化分析及对环境盐度的表达响应

Identification and evolutionary analysis of Claudins gene family in spotted sea bass and its expression characteristics in gill tissue under different salinity

Claudin(cldn)是细胞间紧密连接蛋白的重要功能和结构组件,通过控制细胞旁通路通透性参与渗透压平衡的调节。本研究对花鲈(Lateolabrax maculatus)cldns基因家族进行了系统的鉴定分析,结果表明:花鲈cldns基因家族共包含55个成员,分布于16条染色体上,其中34个cldns基因在哺乳动物体内有对应直系同源基因,其余21个cldns是硬骨鱼所特有。选择压力分析显示预测的花鲈cldns蛋白的跨膜区域存在14个受正选择作用的氨基酸位点,这些正选择位点可能与家族内基因的多样性和功能分化有关。此外,基于花鲈鳃转录组的基因表达结果表明,至少有24个cldns基因在鳃中表达,其中cldn8c、cldn10b、cldn10c、cldn10d、cldn27a和cldn30b在不同环境盐度处理后表达差异显著,表明其可能是花鲈鳃组织中调节渗透压平衡的候选功能基因。本研究成果为研究花鲈及其他广盐性鱼类cldns基因家族成员的渗透调节机制奠定了理论基础。

Claudin(cldn)is an important functional and structural component of the intercellular tight junction protein,which is involved in the regulation of osmotic pressure balance by controlling the permeability of cellular bypass pathways.In the present study,cldn gene family was systematically identified and characterized in spotted sea bass(Lateolabrax maculatus).The results showed that there were 55 members in cldns gene family of spotted sea bass,which were distributed on 16 chromosomes.Among them,34 members have their direct homologous genes in mammals,and the remaining 21 cldns genes seemed to be teleosts-specific.Selection pressure analysis showed that 14 amino acid sites were positively selected in the predicted transmembrane region of cldns protein,which may be associated with the gene diversity and functional differentiation within the family.Additionally,the expression levels of at least 24 cldns genes were detected in the transcriptome of gills in spotted sea bass and cldn8c、cldn10b、cldn10c、cldn10d、cldn27a and cldn30b showed significant expression differences between different salinity environment,suggesting their key roles in regulating osmotic pressure balance in gills of spotted sea bass.This study provides a theoretical basis for studying the osmotic regulation mechanism of cldns gene family in spotted sea bass and other teleosts.