Generation of new model for egg chorion formation in fish

在硬骨鱼中，卵毛膜蛋白的起源被认为是物种特异性的。卵细胞绒毛膜形成（绒毛膜发生）可分为以下两种类型：鱼卵绒毛膜前体（Chg）在母体肝脏中合成（肝型），用卵巢来源的透明带蛋白（ZP）构建绒毛膜（卵巢型）。虽然在一些鱼类中观察到肝脏型鱼的Chgs和卵巢型鱼的ZPs，但尚未研究肝脏型鱼的ZP和卵巢型鱼的Chg。本研究在肝型鱼（鲑科）中观察到了ZP的基因表达和蛋白定位，在卵巢型鱼（鲤科）中鉴定了Chg基因。这些结果提出了硬骨鱼绒毛膜发生需要Chg和ZP的新假设。

In teleost fishes, an origin of egg chorion proteins was considered to be species-specific. Egg chorion formation (choriogenesis) could be divided into following two types; the fish synthesize egg chorion precursors (choriogenin; Chg) in the maternal liver (liver-type) and the fish constructing chorion with ovary-derived zona pellucida (ZP) proteins (ovary-type). Although Chgs in liver-type fish as well as ZPs in ovary-type fish were observed in several fish species, it has not been investigated that ZP in liver-type fish or Chg in ovary-type fish. In the present study, a gene expression and protein localization of ZP in liver-type fish (Salmonid) was observed, while Chg genes in ovary-type fish (Cyprinid) was identified. These results could propose the new hypothesis that both Chg and ZP were required in teleost choriogenesis.