石斑鱼一氧化氮合酶cDNA的分子克隆及序列分析

一氧化氮合酶(nitricoxidesynthase,NOS)专一性催化L-精氨酸转化为L-瓜氨酸和一氧化氮(nitricoxide,NO),产物NO是一种重要的生物信使分子,对其功能和代谢的研究越来越受人们的重视[1]。国际上,鱼类NOS的研究还刚起步,已有研究者在鱼类中检测到NOS的存在[2-5]。虹鳟[6]、金鱼[4]、大西洋鲑[7]和沟鲶[8]的诱导型NOS(iNOS)和神经型NOS(nNOS)的部分序列已鉴定。国内对哺乳动物的NOS也进行了研究[9-11],尚未见关于鱼类NOS方面的研究报道。JOURNALOFFISHERIESOFCHINA　　　　　　　　　　　Vol.27,No.4　斜带石斑鱼(Epin…

Molecular cloning and sequence analysis of nitric oxide synthase gene from Epinephelus coioites

Nitric oxide (NO) is a highly reactive, labile gas produced by the enzymatic conversion of L-arginine by nitric oxide synthases NOS. In mammals, NO mediates multiple physiological processes from cardiovascular control to neural transmission. Three NOS isoforms neuronal, inducible and endothelial have been cloned, sequenced and characterized from several mammalian species. nNOS isoforms were characterized from adult grouper (Epinephelus coioides) by using RT-PCR with degenerate oligonucleotide primers designed against a portion of the mammalian NOS gene that codes for the calmodulin -binding region, this region was chosen because it is highly conserved among NOS sequences to date and is a functionally important region of NOS proteins. A partial gene sequence of 377 bp corresponding to mammalian nNOS is obtained. This sequence showed 82%-83%, 85%-93% homogeneity with that of mammalian and the other fish respectively. The deduced amino acid of E.coioides shows high identity with that of mammalian (92%-93%), and the other fish (93%-99%). Phylogenetic analysis of these sequences confirms the conserved nature of NOS, particularly of the calmodulin-binding domains.