IDENTIFICATION OF A GENE THAT REGULATES EXPRESSION OF M-PROTEIN, THE MAJOR VIRULENCE DETERMINANT OF GROUP-A STREPTOCOCCI
IDENTIFICATION OF A GENE THAT REGULATES EXPRESSION OF M-PROTEIN, THE MAJOR VIRULENCE DETERMINANT OF GROUP-A STREPTOCOCCI
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DOI：
10.1073/pnas.84.23.8677
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发表时间：
1987-12-01
影响因子：
11.1
通讯作者：
SCOTT, JR
中科院分区：
文献类型：
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作者：
CAPARON, MG;SCOTT, JR
通过使用Tn916插入诱变，我们已经鉴定出mry （M蛋白RNA产量），这是一个高水平表达M蛋白所需的基因，M蛋白是a群链球菌的基本毒力决定因素。mry::Tn916突变导致了1倍的减少。在原始菌株和通过转导将突变转移到的未突变宿主中，M蛋白的产生量为50。插入位置位于.apprxeq。M蛋白（emm）及其启动子结构基因上游1.8千碱基。将包含mry::Tn916和emm的基因组区克隆到cosmid载体上，导入大肠杆菌。当转座子从大肠杆菌的嵌合细胞中精确切除时，所得到的链球菌DNA显示出与亲本未诱变链球菌的同源染色体区域相同的限制性模式。在mry突变体中，emm的启动子序列没有改变。蛋白质的减少与M蛋白特异性mRNA数量的减少相关，表明mry调节emm的转录。
By using Tn916 insertional mutagenesis, we have identified mry (M protein RNA yield), a gene required for high-level expression of the M protein, the essential virulence determinant of the group A streptococcus. The mry::Tn916 mutation causes a reduction by a factor of .apprxeq. 50 in the amount of M protein produced, in the original strain and in a nonmutagenized host to which the mutation was transferred by transduction. The insertion is located .apprxeq. 1.8 kilobases upstream of the structural gene for M protein (emm) and its promoter. The genomic region including mry::Tn916 and emm was cloned on a cosmid vector and introduced into Escherichia coli. When the transposon excised precisely from the chimeric cosmid in E. coli, the resulting streptococcal DNA showed the same restriction pattern as the homologous chromosomal region in the parental nonmutagenized streptococcus. The sequence of the promoter for emm was not altered in the mry mutant. The reduction in protein correlates with a decrease in the amount of M protein-specific mRNA, indicating that mry regulates transcription of emm.