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 Electrophorus electricus (electric eel) is still lacking. In this study, we identified 114 TK genes in the E electricus 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）在调节生物体的多细胞性中起关键作用，主要参与细胞生长，分化和细胞间通讯。在许多后生动物中已经对传统知识进行了全基因组表征。但是，仍然缺少有关电泳（电鳗）中这个超家族的系统信息。在这项研究中，我们鉴定了E电器中的114个TK基因基因组，并使用系统发育图谱研究了它们的进化，分子特征和域结构，以更好地了解它们的相似性和特异性。我们的结果表明，电鳗传统知识（EeTK）库由全基因组重复（WGD）和串联重复事件决定。与其他脊椎动物TK相比，Jak，Src和EGFR亚家族的基因成员特异性复制，但在鳗鱼的Eph，Axl和Ack亚家族中丢失的成员。我们还对基因组数据库中的TK基因进行了详尽的调查，确定了涵盖所有主要后生谱系的31个代表性物种中的1674 TK蛋白。广泛的进化分析表明，脊椎动物中的TK种类倾向于得到显着的保守，但是每个亚科的基因成员变化很大。比较表达谱分析表明，电器官组织和肌肉与特定的高度表达的TK（即epha7，麝香，jak1和pdgfra）具有相似的模式，这表明TK的调控可能在确定来自它的肌肉前兆。我们进一步确定了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，代表了不同组织的表现所需要的进化差异。这项工作为进一步的基因功能分析和鉴定候选TK基因产生了有价值的信息，这些基因反映了它们在电鳗中独特的组织功能专长。