CSIR - Centre for Cellular and Molecular Biology, Uppal Road Hyderabad - 500007, India.
Present address: National Centre for Cell Science (NCCS), NCCS Complex, University of Pune Campus, Pune University Rd, Ganeshkhind, Pune, 411007, India.
Microbiology (Reading). 2023 Aug;169(8). doi: 10.1099/mic.0.001359.
A major virulence trait of () is its ability to enter a dormant state within its human host. Since cell division is intimately linked to metabolic shut down, understanding the mechanism of septum formation and its integration with other events in the division pathway is likely to offer clues to the molecular basis of dormancy. The genome lacks obvious homologues of several conserved cell division proteins, and this study was aimed at identifying and functionally characterising mycobacterial homologues of the septum site specification protein MinD ( MinD). Sequence homology based analyses suggested that the genomes of both and the saprophyte () encode two putative MinD homologues and . Of these, were found to be the true homologues, through complementation of the mutant HL1, overexpression studies, and structural comparisons. and fully complemented the mini-cell phenotype of HL1, and over-expression of in led to cell elongation and a drastic decrease in c.f.u. counts, indicating its essentiality in cell-division. MSMEG_3743 displayed ATPase activity, consistent with its containing a conserved Walker A motif. Interaction of Rv1708 with the chromosome associated proteins ScpA and ParB, implied a link between its septum formation role, and chromosome segregation. Comparative structural analyses showed Rv1708 to be closer in similarity to Ec MinD than Rv3660c. In summary we identify Rv1708 and MSMEG_3743 to be homologues of MinD, adding a critical missing piece to the mycobacterial cell division puzzle.
一种主要的毒力特征是其能够在人类宿主中进入休眠状态。由于细胞分裂与代谢关闭密切相关，因此了解隔膜形成的机制及其与分裂途径中其他事件的整合，可能为休眠的分子基础提供线索。基因组缺乏几个保守细胞分裂蛋白的明显同源物，本研究旨在鉴定和功能表征分枝杆菌隔膜位点指定蛋白 MinD (MinD)的同源物。基于序列同源性的分析表明，和腐生菌（）的基因组都编码两个假定的分枝杆菌 MinD 同源物和。通过对 HL1 突变体的互补、过表达研究和结构比较，发现和是真正的同源物。和完全互补 HL1 的迷你细胞表型，并且在中过表达导致细胞伸长和 c.f.u.计数急剧下降，表明其在细胞分裂中是必需的。MSMEG_3743 显示 ATP 酶活性，与其含有保守的 Walker A 基序一致。Rv1708 与染色体相关蛋白 ScpA 和 ParB 的相互作用表明其隔膜形成作用与染色体分离之间存在联系。比较结构分析表明，Rv1708 与 Ec MinD 的相似度比 Rv3660c 更接近。总之，我们鉴定出 Rv1708 和 MSMEG_3743 是 MinD 的同源物，为分枝杆菌细胞分裂难题增添了关键的缺失部分。
