Pestova E V, Håvarstein L S, Morrison D A
Department of Biological Sciences, University of Illinois at Chicago 60607, USA.
Mol Microbiol. 1996 Aug;21(4):853-62. doi: 10.1046/j.1365-2958.1996.501417.x.
The regulation of competence for genetic transformation in Streptococcus pneumoniae depends on a quorum-sensing system, but the only molecular elements of the system whose specific role have been identified are an extracellular peptide signal and an ABC-transporter required for its export. Here we show that transcription of comC, the gene encoding a predicted 41-residue precursor peptide that is thought to be processed and secreted as the 17-residue mature competence activator, increased approximately 40-fold above its basal level of expression in response to exogenous synthetic activator, consistent with earlier experiments indicating that the activator acts autocatalytically. We also describe two new genes, comD and comE, that encode members of histidine protein kinase and response-regulator families and are linked to comC. Disruption of comE abolished both response to synthetic activator peptide and endogenous competence induction.
肺炎链球菌中遗传转化能力的调控依赖于一种群体感应系统，但该系统中唯一已确定其特定作用的分子元件是一种细胞外肽信号及其输出所需的ABC转运蛋白。我们在此表明，comC基因（编码一种预测的41个残基的前体肽，该前体肽被认为会被加工并分泌为17个残基的成熟感受态激活剂）的转录，在响应外源性合成激活剂时，其表达水平比基础水平增加了约40倍，这与早期实验表明激活剂具有自催化作用一致。我们还描述了两个新基因comD和comE，它们编码组氨酸蛋白激酶家族和响应调节因子家族的成员，并且与comC相连。comE的破坏消除了对合成激活剂肽的反应以及内源性感受态诱导。
