Raynor Malik J, Roh Jung-Hyeob, Widen Stephen G, Wood Thomas G, Koehler Theresa M
Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.
University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA.
Mol Microbiol. 2018 Mar 31. doi: 10.1111/mmi.13961.
Bacillus anthracis produces three regulators, AtxA, AcpA and AcpB, which control virulence gene transcription and belong to an emerging class of regulators termed 'PCVRs' (Phosphoenolpyruvate-dependent phosphotransferase regulation Domain-Containing Virulence Regulators). AtxA, named for its control of toxin gene expression, is the master virulence regulator and archetype PCVR. AcpA and AcpB are less well studied. Reports of PCVR activity suggest overlapping function. AcpA and AcpB independently positively control transcription of the capsule biosynthetic operon capBCADE, and culture conditions that enhance AtxA level or activity result in capBCADE transcription in strains lacking acpA and acpB. We used RNA-Seq to assess the regulons of the paralogous regulators in strains constructed to express individual PCVRs at native levels. Plasmid and chromosome-borne genes were PCVR controlled, with AtxA, AcpA and AcpB having a ≥ 4-fold effect on transcript levels of 145, 130 and 49 genes respectively. Several genes were coregulated by two or three PCVRs. We determined that AcpA and AcpB form homomultimers, as shown previously for AtxA, and we detected AtxA-AcpA heteromultimers. In co-expression experiments, AcpA activity was reduced by increased levels of AtxA. Our data show that the PCVRs have specific and overlapping activity and that PCVR stoichiometry and potential heteromultimerization can influence target gene expression.
炭疽芽孢杆菌产生三种调节因子，即AtxA、AcpA和AcpB，它们控制毒力基因转录，属于一类新出现的调节因子，称为“PCVRs”（含磷酸烯醇丙酮酸依赖性磷酸转移酶调节结构域的毒力调节因子）。AtxA因其对毒素基因表达的控制而得名，是主要的毒力调节因子和PCVR原型。对AcpA和AcpB的研究较少。关于PCVR活性的报道表明它们具有重叠功能。AcpA和AcpB独立地正向控制荚膜生物合成操纵子capBCADE的转录，并且增强AtxA水平或活性的培养条件会导致在缺乏acpA和acpB的菌株中capBCADE转录。我们使用RNA测序来评估在构建的以天然水平表达单个PCVR的菌株中这些同源调节因子的调控子。质粒和染色体携带的基因受PCVR控制，AtxA、AcpA和AcpB分别对145、130和49个基因的转录水平有≥4倍的影响。几个基因由两个或三个PCVR共同调节。我们确定AcpA和AcpB形成同多聚体，如先前对AtxA的研究所示，并且我们检测到AtxA-AcpA异多聚体。在共表达实验中，AtxA水平的增加会降低AcpA的活性。我们的数据表明PCVR具有特定和重叠的活性，并且PCVR的化学计量和潜在的异多聚化可以影响靶基因的表达。
