A DUAL TRANSCRIPTIONAL ACTIVATION SYSTEM FOR THE 230 KB PLASMID GENES-CODING FOR VIRULENCE-ASSOCIATED ANTIGENS OF SHIGELLA-FLEXNERI
A DUAL TRANSCRIPTIONAL ACTIVATION SYSTEM FOR THE 230 KB PLASMID GENES-CODING FOR VIRULENCE-ASSOCIATED ANTIGENS OF SHIGELLA-FLEXNERI
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DOI：
10.1111/j.1365-2958.1989.tb00210.x
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发表时间：
1989-05-01
影响因子：
3.6
通讯作者：
YOSHIKAWA, M
中科院分区：
文献类型：
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作者：
ADLER, B;SASAKAWA, C;YOSHIKAWA, M
研究发现，福氏志贺氏菌质粒编码的入侵相关抗原IPa b、c和d的表达在转录水平上受到一个33kD蛋白的正调控，该蛋白由先前定义的230kb入侵质粒SalI片段b上的毒力相关区1产生。鉴定了该基因（命名为virB）并确定了其核苷酸序列。在没有完整virB基因的情况下，不产生Ipa b或c，但产生较低水平的d。先前报道的30 kb外的virF基因的调控活性被证明只通过virB起作用。相反，virF直接激活了细胞间传播所必需的virG基因，而不需要virB。因此，这项研究归因于先前认识到的，但功能上未定义的，大型入侵质粒上的毒力位点的关键功能。virF基因似乎在激活230 kb质粒编码的毒力基因中起核心作用。
The expression of plasmid-encoded, invasion-related antigens IPa b, c and d of Shigella flexneri was found to be positively regulated at transcriptional level by a 33kD protein produced by the previously defined, virulence-associated Region 1 on the SalI fragment B of the 230 kb invasion plasmid. The gene (designated virB) was identified and its nucleotide sequence determined. No Ipa b or c was produced in the absence of an intact virB gene although lower levels of d were produced. The previously reported regulatory activity of the virF gene some 30 kb distance away was shown to act exclusively through virB. In contrast, the activation of the virG gene necessary for intercellular spread occurred directly by virF without the requirement for virB. This study thus ascribes a critical function to a preriously recognized, but functionnally undefined, virulence locus on the large invasion plasmid of S. flexneri. The virF gene appears to have a central role in activation of the 230 kb plasmid-encoded virulence genes.