Belitsky Boris R, Barbieri Giulia, Albertini Alessandra M, Ferrari Eugenio, Strauch Mark A, Sonenshein Abraham L
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA.
Dipartimento di Biologia e Biotecnologie 'Lazzaro Spallanzani', Università di Pavia, Pavia, Italy.
Mol Microbiol. 2015 Aug;97(4):698-716. doi: 10.1111/mmi.13056. Epub 2015 Jun 6.
CodY and ScoC are Bacillus subtilis transcriptional regulators that control the expression of dozens of genes and operons. Using scoC-lacZ fusions and DNA-binding experiments, we show here that scoC is directly repressed by CodY. This effect creates multiple forms of cascade regulation. For instance, expression of the dtpT gene, which is directly and negatively controlled by ScoC and encodes a putative oligopeptide permease, was activated indirectly by CodY due to CodY-mediated repression of scoC. The opp operon, which encodes an oligopeptide permease that is essential for sporulation and genetic competence development, proved to be a direct target of repression by both ScoC and CodY but was not significantly affected in codY or scoC single mutants. The combined actions of CodY and ScoC maintain opp repression when either one of the regulators loses activity but limit the level of repression to that provided by one of the regulators acting alone. Under conditions of nitrogen limitation, repression by ScoC of dtpT and opp was partly prevented by TnrA. Thus, the functioning of ScoC is determined by other transcription factors via modulation of its expression or DNA binding.
CodY和ScoC是枯草芽孢杆菌的转录调节因子，可控制数十个基因和操纵子的表达。通过使用scoC - lacZ融合体和DNA结合实验，我们在此表明scoC直接受到CodY的抑制。这种效应产生了多种形式的级联调节。例如，dtpT基因直接受到ScoC的负调控，编码一种假定的寡肽通透酶，由于CodY介导的对scoC的抑制，其表达被CodY间接激活。opp操纵子编码一种对孢子形成和遗传感受态发展至关重要的寡肽通透酶，被证明是ScoC和CodY直接抑制的靶标，但在codY或scoC单突变体中没有受到显著影响。当其中一个调节因子失去活性时，CodY和ScoC的联合作用维持对opp的抑制，但将抑制水平限制在由单独一个调节因子提供的水平。在氮限制条件下，TnrA部分阻止了ScoC对dtpT和opp的抑制。因此，ScoC的功能是由其他转录因子通过调节其表达或DNA结合来决定的。
