Inferring the Evolution of Teleostean zp Genes Based on Their Sites of Expression
Inferring the Evolution of Teleostean zp Genes Based on Their Sites of Expression
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DOI：
10.1002/jez.b.22507
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发表时间：
2013-07-01
影响因子：
2.2
通讯作者：
Yasumasu, Shigeki
中科院分区：
文献类型：
--
作者：
Sano, Kaori;Kawaguchi, Mari;Yasumasu, Shigeki
鱼卵膜由几种糖蛋白组成，称为透明带(ZP)蛋白，在脊索动物中保守。真核生物在肝脏中合成ZP蛋白，而真核生物在卵巢中合成ZP蛋白。在鲤形目鱼类中，ZP基因在卵巢中表达。我们研究了两个耳头目的ZP基因：Clupeiformes(太平洋鲱鱼和日本凤尾鱼)和Gonorynchiformes(牛奶鱼)，它们比鲤形目分化得更早。ZP基因同源物的克隆表明，太平洋鲱鱼和日本凤尾鱼同时具有卵巢和肝脏表达的ZP基因，而银鱼的ZP基因只在卵巢表达。分子系统发育分析表明，这两个类的卵巢和肝脏表达的zpc基因形成了独立的分支。在此基础上，我们假设了硬骨动物ZP基因的进化，重点放在表达ZP基因的器官上。与其他脊索动物一样，ZP基因的最初表达部位可能是卵巢。在硬骨动物进化的早期阶段，祖先的ZP基因获得了在肝脏表达的能力。后来，两个表达位点中的一个成为主导。肝脏表达的ZP基因是真甲藻卵膜的组成蛋白。在耳头鱼中，Clupeiformes同时具有卵巢和肝脏表达的基因，这些基因可能参与卵膜的形成，而淋巴形目和鲤形目则主要保存了卵巢表达的ZP基因。J.Exp.祖尔。(摩尔。戴夫。320B：332-343,2013。(C)2013年威利期刊公司。
Fish egg envelopes consist of several glycoproteins, called zona pellucida (ZP) proteins, which are conserved among chordates. Euteleosts synthesize ZP proteins in the liver, while elopomorphs synthesize them in the ovaries. In Cypriniformes, zp genes are expressed in the ovaries. We investigated the zp genes of two Otocephalan orders: Clupeiformes (Pacific herring and Japanese anchovy) and Gonorynchiformes (milkfish), which diverged earlier than Cypriniformes. cDNA cloning of zp gene homologs revealed that Pacific herring and Japanese anchovy possessed both ovary- and liver-expressed zp genes; however, the zp genes of milkfish were only expressed in the ovaries. Molecular phylogenetic analysis showed that ovary- and liver-expressed zpc genes of two the Clupeiformes formed independent clades. Based on this, we hypothesized the evolution of teleostean zp genes, focusing on the organ expressing zp gene. As in other chordates, the original site of expression of zp genes was likely the ovary. In the early stage of teleostean evolution, the ancestral zp genes acquired the ability to express in the liver. Later, one of the two expression sites became dominant. The liver-expressed zp genes are component proteins of the egg envelope in the Euteleostei. In Otocephala, Clupeiformes possess both ovary- and liver-expressed genes that presumably participate in egg envelope formation, whereas the Gonorynchiformes and Cypriniformes have primarily preserved ovary expressed zp genes. J. Exp. Zool. (Mol. Dev. Evol.) 320B:332-343, 2013. (c) 2013 Wiley Periodicals, Inc.