鲤鱼肝胰脏cDNA 文库的表达序列标签分析及Lb-Fabp mRNA的特征

本文构建了鲤鱼肝胰脏cDNA 文库，共获得了1016条有效的表达序列标签。拼接组装成115 个contigs和282 个singletons。其中215个拼接序列在GenBank公共数据库中寻找到相对应的基因。对它们进行功能性分类和比较分析为鲤鱼肝胰脏的研究提供了基因表达信息的基础。文库中1016条表达序列标签有11条代表了鲤鱼肝基本型脂肪酸结合蛋白(Lb-FABP)。通过序列比较我们获得了两个具有相同开放阅读框长度的Lb-Fabp cDNAs。开放阅读框全长381bp，编码126个氨基酸。半定量RT-PCR结合Southern blot技术研究了Lb-Fabp mRNA 在成鱼不同组织以及早期发育不同时期的表达图式。结果表明，Lb-Fabp mRNA 在肝胰脏、中肠和后肠中表达量较高。同时在精巢和皮肤中有低水平的表达。脑、肌肉、卵巢、肾脏、脾脏、鳃和心脏等组织中其表达量更低。而在脂肪和前肠中则没有检测到Lb-FabpmRNA表达。Lb-Fabp mRNA 最早在胚体形成期检测到有低水平表达，随后的发育阶段中表达量逐渐升高。鲤鱼Lb-Fabp基因的表达图式提示在肝脏和肠等器官开始发育后，它可能在脂肪代谢中具有重要作用。

Analysis of expressed sequence tags from Hepatopancreatic cDNA library of common carp (Cyprinus carpio) and characterization of Lb-Fabp mRNA

A representative cDNA library obtained from hepatopanereas of common carp (Cyprinus carpio) was constructed, and 1016 expressed sequence tags were generated assembling into 115 contiguous sequences and 282 singletons. 215 (54.15%) of the assembled sequences were annotated based upon matching known genes in the GenBank public Databas-es. Functional categorization and comparative analyses of the sequence provided gene identities, expression information and a solid base for further research on common carp hepatopancreas. High expression of liver basic fatty acid binding protein (Lb-Fabp) (11/1016 ESTs) in the library was detected. Two types of Lb-Fabpa and Lb-Fabpb had an open reading frame of 381 bp encoding 126 amino acids, mRNA expression of Lb-Fabps in embryos, larva and adult common carp tissues were determined using semi-quantitative RT-PCR followed by Southern Blot analysis. Lb-Fabp mRNA was expressed with high levels in hepatopancreas, middle intestine and posterior intestine. Low levels of Lb-Fabp mRNA expression were observed in testis and skin, while much lower levels in muscle, brain, ovary, kidney, spleen, gill and heart. No Lb-Fabp mRNA expression was observed in fat and anterior intestine. Lb-Fabp mRNA was first observed in neurula stage, and expressed higher in the following stages. The expression pattern of Lb-Fabp mRNA suggests that common carp Lb-FABPs play an im-portant role in lipid metabolism after the morphogenesis of hepatopancreas and intestine.