萼花臂尾轮虫非混交雌体SOX基因的克隆与分析  

Clone and sequence analysis of SOX genes in amictic females of rotifer Brachionus calyciflorus

作　　者：李大命[1] 孙显[1] 杨家新[1] 

机构地区：[1]南京师范大学生命科学学院,南京210046

出　　处：《淡水渔业》2010年第5期3-8,共6页Freshwater Fisheries

基　　金：国家自然科学基金(30371093)

摘　　要：选用根据SOX基因蛋白序列设计的1对兼并引物,采用PCR技术扩增萼花壁尾轮虫(Brachionus calyciflorus)非混交雌体基因组DNA。结果显示:实验得到1个约220 bp的片段。经过克隆和测序分析,共获得2个有差异的DNA片段,其中一个DNA片段证明为萼花臂尾轮虫SOX2蛋白编码序列,与人和秀丽隐杆线虫(Cae-norhabditis elegans)DNA序列碱基组成相似性分别为68.98%和75.93%,其编码的氨基酸序列与人、秀丽隐杆线虫SOX2蛋白相似性分别为为84.72%和81.94%。另一个DNA片段长209 bp,用BLAST程序在GenBank数据库中搜索,没有找到相似性序列,用该序列推导氨基酸序列,发现两个终止密码子,推测该片段是受到自然选择作用失去功能的SOX基因。同时对多个物种的SOX2基因保守序列进行比对,发现萼花臂尾轮虫SOX2基因是一种古老的基因形式,具有高度的保守性。A pair of degenerate primers designed according to existing SOX proteins were used to amplified genomics of Brachionus calyciflorus by PCR and the 220 bp band was obtained.Two different fragments of SOX genes were selected and sequenced from the 220 bps band.One of the two fragments was proved to be SOX2 subfamily and the similarity percentage of base composition corresponding to human and Caenorhabditis elegans SOX2 sequence were 68.98% and 75.93% respectively,meanwhile the protein sequence deduced from DNA sequence was about 84.72% and 81.94% identity respectively.The other 209 bp sequence was found no similar sequences by Blast searching in GenBank and two stop codons in this sequence were found out.The sequence was supposed to be SOX gene that had lost its function under nature selection.Many SOX2 proteins of different species obtained from GenBank were compared and the results revealed that B.calyciflorus SOX2 protein was an ancient gene type and highly conserved.

关 键 词：萼花臂尾轮虫(Brachionus calyciflorus) 非混交雌体 SOX基因 性别决定 

分 类 号：S963.214[农业科学—水产养殖] Q173[农业科学—水产科学]