极大节旋藻(Arthrospira maxima)生物钟基因kaiC的克隆及分析  

Cloning and sequence analyses of circadian clock gene kaiC in Arthrospira maxima

作　　者：刘玮[1] 茅云翔[1] 凌娜[1] 王孟强[1] 崔菁菁[1] 

机构地区：[1]中国海洋大学海洋生命学院

出　　处：《高技术通讯》2008年第4期429-435,共7页Chinese High Technology Letters

基　　金：国家自然科学基金(30200208;30571418)资助项目

摘　　要：以 kaiC 基因簇部分已知序列为引物设计位点,采用 PCR 反应池法从节旋藻基因组 fosmid 文库中筛选到 kaiC 基因克隆,通过步移测序获得了 kaiC 基因全长序列。kaiC基因编码区长1554 bp,基因 GC 碱基含量平均为41.76%,密码子第三位明显偏向于 U。在基因上游385 bp 范围内发现一个可能的启动子序列和一些基因调控元件。KaiC 蛋白分析发现了 Walker A、DXXG、不完整的 Walker B 等重要模体和具有催化作用的功能位点。Southern 杂交的结果证明 kaiC 基因在极大节旋藻中为单拷贝。极大节旋藻 kaiC 基因的特殊结构特征为研究 kai 基因簇的进化提供了重要的启示。The fosmid clone carrying the circadian gene kaiC was isolated from Arthrospira maxima fosmid DNA hbrary by PCR-pooling based on partial known sequence, and then the full length of kaiC gene was obtained by sequence walking. The coding region of the kaiC gene consists of 1554 bp nucleotide acids. The average GC content of kaiC gene is 41.76% and the third position of codon has a strong bias towards U. A possible kaiC promoter.and some regulation elements were found in 5＇UTR of kaiC gene which consists of 385 bp. The analyses of amino acid sequence demonstrate KaiC protein contain some vital motifs and functional sites, such as Walker A motif, imperfect Walker motif B, DXXG motif, two deduced catalytic Glu residues and so on. Southern blot result shows that the kaiC gene is present as a single copy in the genome of Arthrospira maxima. The profile of the kaiC gene of Arthrospira maxima provides an important clue to the molecular evolution study of kai gene cluster.

关 键 词：节旋藻 生物钟基因 kaiC基因 分子进化 

分 类 号：Q943.2[生物学—植物学]