鱼腥藻PCC7120基因all3211和asl3212的克隆及其功能鉴定  

CLONING AND IDENTIFICATION OF GENES ALL3211 AND ASL3212 IN THE CHROMOSOME OF ANABAIENA SP.PCC7120

作　　者：梅菊[1] 陈思礼[1] 刘欣[1] 尤隽丹[1] 

机构地区：[1]中南民族大学生命科学学院,湖北武汉430074

出　　处：《陕西科技大学学报（自然科学版）》2012年第1期15-20,共6页Journal of Shaanxi University of Science & Technology

基　　金：国家自然科学基金项目(31001099/C190101);湖北省全球基金艾滋病项目(SZY10008);中南民族大学重点实验室项目(XJS09002)

摘　　要：鱼腥藻PCC7120染色体上的开放阅读框all3211和asl3212具有与大肠杆菌细胞染色体上毒素-抗毒素系统(TA,toxin-antitoxin system)相同的遗传结构,该系统由位于同一操纵子中的两个分别编码毒素蛋白和抗毒素蛋白的基因组成,介导细胞程序性死亡.基因all3211的编码产物与MazEF毒素-抗毒素系统中的毒素蛋白MazF同源.为证明这一对基因表达产物的毒素抗毒素作用,首先设计合适引物克隆了鱼腥藻PCC7120染色体上all3211和asl3212基因,并构建了含乳糖启动子和阿拉伯糖启动子的双启动子表达载体,将两个基因分别置于该载体的不同启动子下进行诱导表达,验证了各自表达产物对细胞的作用.结果显示:all3211基因的表达产物对细胞有一定的毒性作用,可抑制细胞生长;asl3212基因表达产物能减弱all3211表达产物对细胞的毒性作用,初步证明这一对基因构成了一个毒素-抗毒素系统,all3211为毒素基因,asl3212为抗毒素基因.The genetic organization of an open reading frame（ORF）, all3211 and asl3212 , in the chromosome of Anabaena sp. PCC7120, is similar to that of the toxin-antitoxin（TA） sys- tems in the chromosome of E. coli. The TA system consists of a pair of genes in the same promoter, encoding toxin protein and antitoxin protein, mediates programmed cell death （PCD）. The protein ecoded by all3211 is homologous to MazF. To prove whether all3211 encodes a toxin protein, asl3212 encodes an antitoxin, all3211 and asl3212 genes were cloned by PCR and an expressing vector with two promoter PBAD and Plac was constructed. Both all3211 and asl3212 were controlled by PBAD and Plac. Inducing this two gene expressing to tested the function of the expression products to cells. The results show that the product of all3211 inhibites the E. coil cell growth and the product of all3211 can weaken the toxicity of all3211 expression. Peliminary proves both all3211 and asl3212 constitute a TA system in Anabaena sp. PCC7120, all3211 is toxin gene, asl3212 is antitoxin gene.

关 键 词：鱼腥藻PCC7120 TA系统 all3211 asl3212 

分 类 号：Q78[生物学—分子生物学]