ParA of Mycobacterium smegmatis co-ordinates chromosome segregation with the cell cycle and interacts with the polar growth determinant DivIVA
ParA of Mycobacterium smegmatis co-ordinates chromosome segregation with the cell cycle and interacts with the polar growth determinant DivIVA
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DOI：
10.1111/mmi.12146
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发表时间：
2013-03-01
影响因子：
3.6
通讯作者：
Jakimowicz, Dagmara
中科院分区：
文献类型：
--
作者：
Ginda, Katarzyna;Bezulska, Martyna;Jakimowicz, Dagmara
分枝杆菌是临床上最重要的病原体之一，但对其细胞周期控制的机制仍知之甚少。以前的研究表明，编码帕拉和ParB（ATP酶和DNA结合蛋白，分别需要主动染色体分离）的基因可能是结核分枝杆菌所必需的。进一步的研究表明，耻垢分枝杆菌parB缺失突变体是可行的，但表现出染色体分离缺陷。在这里，我们解决的问题，如果帕拉是需要的耻垢分枝杆菌的生长，以及它影响的细胞周期过程。我们的数据表明，帕拉可以删除，但它的删除导致生长抑制和染色体分离和隔膜定位的严重干扰。类似的缺陷也是由帕拉生产过剩引起的。EGFPParA定位为与伴随两个ParB复合物的荧光斑块连接的极点相关复合物。在帕拉缺失突变体中观察到的ParB复合物的数量和位置的畸变表明，帕拉是ParB复合物正确定位所必需的。此外，它表明，帕拉共定位和相互作用的极性生长决定因素Wag31（DivIVA同源）。我们的研究结果表明，分枝杆菌帕拉介导染色体分离和协调它与细胞分裂和伸长。
Mycobacteria are among the clinically most important pathogens, but still not much is known about the mechanisms of their cell cycle control. Previous studies suggested that the genes encoding ParA and ParB (ATPase and DNA binding protein, respectively, required for active chromosome segregation) may be essential in Mycobacterium tuberculosis. Further research has demonstrated that a Mycobacterium smegmatis parB deletion mutant was viable but exhibited a chromosome segregation defect. Here, we address the question if ParA is required for the growth of M.smegmatis, and which cell cycle processes it affects. Our data show that parA may be deleted, but its deletion leads to growth inhibition and severe disturbances of chromosome segregation and septum positioning. Similar defects are also caused by ParA overproduction. EGFPParA localizes as pole-associated complexes connected with a patch of fluorescence accompanying two ParB complexes. Observed aberrations in the number and positioning of ParB complexes in the parA deletion mutant indicate that ParA is required for the proper localization of the ParB complexes. Furthermore, it is shown that ParA colocalizes and interacts with the polar growth determinant Wag31 (DivIVA homologue). Our results demonstrate that mycobacterial ParA mediates chromosome segregation and co-ordinates it with cell division and elongation.