Li Ling, Liu Dangyun, Liu Ake, Li Jingquan, Wang Hui, Zhou Jingqi
School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China.
Department of Central Laboratory, The Affiliated Huaian No.1 People's Hospital, Nanjing Medical University, Huai'an, P.R. China.
Evol Bioinform Online. 2020 May 25;16:1176934320922519. doi: 10.1177/1176934320922519. eCollection 2020.
Tyrosine kinases (TKs) play key roles in the regulation of multicellularity in organisms and involved primarily in cell growth, differentiation, and cell-to-cell communication. Genome-wide characterization of TKs has been conducted in many metazoans; however, systematic information regarding this superfamily in (electric eel) is still lacking. In this study, we identified 114 TK genes in the genome and investigated their evolution, molecular features, and domain architecture using phylogenetic profiling to gain a better understanding of their similarities and specificity. Our results suggested that the electric eel TK (EeTK) repertoire was shaped by whole-genome duplications (WGDs) and tandem duplication events. Compared with other vertebrate TKs, gene members in Jak, Src, and EGFR subfamily duplicated specifically, but with members lost in Eph, Axl, and Ack subfamily in electric eel. We also conducted an exhaustive survey of TK genes in genomic databases, identifying 1674 TK proteins in 31 representative species covering all the main metazoan lineages. Extensive evolutionary analysis indicated that TK repertoire in vertebrates tended to be remarkably conserved, but the gene members in each subfamily were very variable. Comparative expression profile analysis showed that electric organ tissues and muscle shared a similar pattern with specific highly expressed TKs (ie, epha7, musk, jak1, and pdgfra), suggesting that regulation of TKs might play an important role in specifying an electric organ identity from its muscle precursor. We further identified TK genes exhibiting tissue-specific expression patterns, indicating that members in TKs participated in subfunctionalization representing an evolutionary divergence required for the performance of different tissues. This work generates valuable information for further gene function analysis and identifying candidate TK genes reflecting their unique tissue-function specializations in electric eel.
酪氨酸激酶（TKs）在生物体多细胞性的调控中发挥关键作用，主要参与细胞生长、分化以及细胞间通讯。许多后生动物已对TKs进行了全基因组特征分析；然而，关于电鳗中这个超家族的系统信息仍然缺乏。在本研究中，我们在电鳗基因组中鉴定出114个TK基因，并利用系统发育分析研究它们的进化、分子特征和结构域架构，以更好地了解它们的相似性和特异性。我们的结果表明，电鳗TK（EeTK）库是由全基因组复制（WGDs）和串联重复事件形成的。与其他脊椎动物的TKs相比，Jak、Src和EGFR亚家族的基因成员发生了特异性复制，但电鳗中Eph、Axl和Ack亚家族的成员有所缺失。我们还对基因组数据库中的TK基因进行了详尽的调查，在涵盖所有主要后生动物谱系的31个代表性物种中鉴定出1674个TK蛋白。广泛的进化分析表明，脊椎动物中的TK库倾向于高度保守，但每个亚家族中的基因成员差异很大。比较表达谱分析表明，电鳗的电器官组织和肌肉具有相似的模式，特定的TKs（即epha7、musk、jak1和pdgfra）高度表达，这表明TKs的调控可能在从肌肉前体确定电器官身份方面发挥重要作用。我们进一步鉴定出表现出组织特异性表达模式的TK基因，表明TKs中的成员参与了亚功能化，这代表了不同组织发挥功能所需的进化分歧。这项工作为进一步的基因功能分析以及鉴定反映电鳗独特组织功能特化的候选TK基因提供了有价值的信息。
