Identification and characterization of a regulatory sequence recognized by Mycobacterium tuberculosis persistence regulator MprA
Identification and characterization of a regulatory sequence recognized by Mycobacterium tuberculosis persistence regulator MprA
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DOI：
10.1128/jb.187.1.202-212.2005
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发表时间：
2005-01-01
影响因子：
3.2
通讯作者：
Zahrt, TC
中科院分区：
文献类型：
--
作者：
He, HJ;Zahrt, TC
结核分枝杆菌持续、潜伏感染的建立和维持依赖于mprA-MPRB调控系统的表达。以往的研究表明，MprA和MprB参与了双组分信号系统特有的磷酸转移反应。为了开始鉴定在持续感染阶段由mprA-mprB调控的下游效应基因，我们搜索了由反应调控因子mprA识别的调控序列(S)。在这里，有证据表明，MprA识别一个19bp的序列，该序列包含两个被3个核苷酸隔开的松散保守的8-bp直接重复亚基。这个基序称为MprA盒，位于mprA编码序列的上游和下游基因PepD(Rv0983)的上游。在体外，MprA与该DNA序列的结合并不需要蛋白质的磷酸化，但在体内，MprA的磷酸化增强了MprA与DNA的结合，并需要MprA对mprA和PepD的调节。MprA与MprA盒的结合依赖于重复亚基中包含的保守核苷酸以及这些重复序列之间的间隔子长度。此外，该序列的识别是通过MprA的两个单体的串联结合进行的。识别受MprA调控的遗传决定因素将最终加强我们对结核分枝杆菌潜伏期机制的理解。
Establishment and maintenance of persistent, latent infection by Mycobacterium tuberculosis are dependent on expression of the mprA-mprB regulatory system. Previously, MprA and MprB were shown to participate in phosphotransfer reactions characteristic of two-component signaling systems. To begin identifying downstream effector genes regulated by mprA-mprB during persistent stages of infection, a search for the regulatory sequence(s) recognized by response regulator MprA was carried out. Here, evidence is presented demonstrating that MprA recognizes a 19-bp sequence comprising two loosely conserved 8-bp direct repeat subunits separated by 3 nucleotides. This motif, termed the MprA box, is found upstream of the mprA coding sequence and that of downstream gene pepD (Rv0983). Protein phosphorylation was not required for binding to this DNA sequence by MprA in vitro; however, phosphorylation enhanced DNA binding by MprA and was required for the regulation of mprA and pepD by MprA in vivo. Binding of MprA to the MprA box was dependent on conserved nucleotides contained within repeat subunits and on the spacer length separating these repeats. In addition, recognition of this sequence proceeded via tandem binding of two monomers of MprA. Identification of the genetic determinants regulated by MprA will ultimately enhance our understanding of the mechanisms utilized by M. tuberculosis to undergo latency.