小立碗藓CAS基因的克隆及与拟南芥CAS基因的比较  

Cloning and Phylogenetic Analysis of Physcometrella Patants Extracellular Calcium-sensing Receptor (CAS) Gene

作　　者：胡勇[1] 蒋广龙[1] 赵晓刚[2] 周伟巍[1] 

机构地区：[1]首都师范大学生命科学学院,北京100048 [2]北京市第四中学,北京100034

出　　处：《首都师范大学学报（自然科学版）》2008年第6期47-51,共5页Journal of Capital Normal University：Natural Science Edition

基　　金：国家自然科学基金资助(30500288);北京市教委科技发展计划面上项目(KM200610028010);北京市优秀人才项目资助(20051A0501605)

摘　　要：钙信号在动植物的生长、发育过程中具有不可替代的作用.胞外钙受体(Extracellular Calcium-sensing receptor,CAS)是动植物质膜上一种跨膜离子通道蛋白,可以感受胞外Ca2+水平,充当第一信使将胞外的信号传递到细胞内.但迄今为止,仅2003年从植物拟南芥中克隆了胞外钙受体CAS基因,其起源进化我们知之甚少.本实验成功克隆了小立碗藓CAS基因,其cDNA全序列共1 574 bp,5′-非翻译区80个核苷酸,3′-非翻译区234个核苷酸,开放阅读框(ORF)1 257 bp,编码419个氨基酸,共有6个内含子.虽然藓类植物与被子植物进化距离较远,但小立碗藓CAS基因前五个内含子的插入位置以及相位与拟南芥完全相同,这说明植物中CAS基因在漫长的进化过程中非常保守,暗示被子植物胞外钙离子信号感受、传递机制起源于藓类植物.Extracellular Ca2＋ is required for various physiological and developmental processes in animals and plants.Calcium-sensing receptor is a Ca2＋ permeableable channel of cytoplasm membrane,which is essential to maintain relatively constant internal Ca2＋ content.In plants,calcium-sensing receptor（CAS） can sense the level of extra-cellular Ca2＋ and lead closure of stomata.Up to date,however,only one CAS gene was cloned from Arabidopsis by function-cloned method.Whether the CAS genes exist in the other plants remain unclear.In this study,a homologue of Arabidopsis CAS gene was identified from Physcomitrella patens.With a 1 257 bp ORF（opening reading frame）,the full-length 1 574 bp PpCAS cDNA had a 80 bp 5′ UTR（untranslation region） and a 234 bp 3′ UTR,and encoded a precursor of 419 amino acid residues with 38.4% identity with Arabidopsis CAS.Genomic structure comparison between PpCAS Arabidopsis and PpCAS shows that exon length and intron position are conserved except that PpCAS has one more intron,which indicates that the Ca2＋ signal transduction might be an ancient conserved mechanism in land plant.

关 键 词：小立碗藓 CAS(calcium-sensing receptor) 内含子 内含子相位 逆转录PCR 

分 类 号：Q943.2[生物学—植物学]