Wang Y, Zhou L, Li Z, Gui J F
State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan Center for Developmental Biology, Institute of Hydrobiology, Graduate School of the Chinese Academy of Sciences, Wuhan 430072, China.
Fish Physiol Biochem. 2008 Dec;34(4):339-48. doi: 10.1007/s10695-007-9193-y. Epub 2008 Feb 10.
Endogenous yolk nutrients are crucial for embryo and larval development in fish, but developmental behavior of the genes that control yolk utilization remains unknown. Apolipoproteins have been shown to play important roles in lipid transport and uptake through the circulation system. In this study, EcApoC-I, the first cloned ApoC-I in teleosts, has been screened from pituitary cDNA library of female orange-spotted grouper (Epinephelus coioides), and the deduced amino acid sequence shows 43.5% identity to one zebrafish (Danio rerio) hypothetical protein similar to ApoC-I, and 21.2%, 21.7%, 22.5%, 20%, and 22.5% identities to Apo C-I of human (Homo sapiens), house mouse (Mus musculus), common tree shrew (Tupaia glis), dog (Canis lupus familiaris) and hamadryas baboon (Papio hamadryas), respectively. Although the sequence identity is low, amphipathic alpha-helices with the potential to bind to lipid were predicted to exist in the EcApoC-I. RT-PCR analysis revealed that it was first transcribed in gastrula embryos and maintained a relatively stable expression level during the following embryogenesis. During embryonic and early larval development, a very high level of EcApoC-I expression was in the yolk syncytial layer, indicating that it plays a significant role in yolk degradation and transfers nutrition to the embryo and early larva. By the day 7 after hatching, EcApoC-I transcripts were observed in brain. In adult, EcApoC-I mRNA was detected abundantly in brain and gonad. In transitional gonads, the EcApoC-I expression is restricted to the germ cells. The data suggested that EcApoC-I might play an important role in brain and gonad morphogenesis and growth.
内源性卵黄营养物质对鱼类胚胎和幼体发育至关重要，但控制卵黄利用的基因的发育行为仍不清楚。载脂蛋白已被证明在脂质通过循环系统的运输和摄取中发挥重要作用。在本研究中，从雌性斜带石斑鱼（Epinephelus coioides）的垂体cDNA文库中筛选出了硬骨鱼中首个克隆的载脂蛋白C-I（EcApoC-I），其推导的氨基酸序列与一种与载脂蛋白C-I相似的斑马鱼（Danio rerio）假定蛋白具有43.5%的同一性，与人类（Homo sapiens）、家鼠（Mus musculus）、普通树鼩（Tupaia glis）、狗（Canis lupus familiaris）和阿拉伯狒狒（Papio hamadryas）的载脂蛋白C-I分别具有21.2%、21.7%、22.5%、20%和22.5%的同一性。尽管序列同一性较低，但预测EcApoC-I中存在具有结合脂质潜力的两亲性α-螺旋。RT-PCR分析显示，它在原肠胚胚胎中首次转录，并在随后的胚胎发育过程中保持相对稳定的表达水平。在胚胎和幼体早期发育过程中，EcApoC-I在卵黄合胞体层中表达水平非常高，表明它在卵黄降解以及将营养物质传递给胚胎和幼体早期方面发挥着重要作用。孵化后第7天，在脑中观察到EcApoC-I转录本。在成体中，EcApoC-I mRNA在脑和性腺中大量检测到。在过渡性腺中，EcApoC-I的表达仅限于生殖细胞。这些数据表明，EcApoC-I可能在脑和性腺的形态发生和生长中发挥重要作用。
