Letek Michal, Ordóñez Efrén, Vaquera José, Margolin William, Flärdh Klas, Mateos Luis M, Gil José A
Departamento de Biología Molecular, Area de Microbiología, Facultad de Biología, Universidad de León, 24071 León, Spain.
J Bacteriol. 2008 May;190(9):3283-92. doi: 10.1128/JB.01934-07. Epub 2008 Feb 22.
The actinomycete Corynebacterium glutamicum grows as rod-shaped cells by zonal peptidoglycan synthesis at the cell poles. In this bacterium, experimental depletion of the polar DivIVA protein (DivIVA(Cg)) resulted in the inhibition of polar growth; consequently, these cells exhibited a coccoid morphology. This result demonstrated that DivIVA is required for cell elongation and the acquisition of a rod shape. DivIVA from Streptomyces or Mycobacterium localized to the cell poles of DivIVA(Cg)-depleted C. glutamicum and restored polar peptidoglycan synthesis, in contrast to DivIVA proteins from Bacillus subtilis or Streptococcus pneumoniae, which localized at the septum of C. glutamicum. This confirmed that DivIVAs from actinomycetes are involved in polarized cell growth. DivIVA(Cg) localized at the septum after cell wall synthesis had started and the nucleoids had already segregated, suggesting that in C. glutamicum DivIVA is not involved in cell division or chromosome segregation.
放线菌谷氨酸棒杆菌通过在细胞两极进行分区肽聚糖合成，以杆状细胞形式生长。在这种细菌中，极性DivIVA蛋白（DivIVA(Cg)）的实验性缺失导致极性生长受到抑制；因此，这些细胞呈现出球状形态。这一结果表明，DivIVA是细胞伸长和获得杆状形态所必需的。与定位于谷氨酸棒杆菌隔膜处的枯草芽孢杆菌或肺炎链球菌的DivIVA蛋白不同，来自链霉菌或分枝杆菌的DivIVA定位于DivIVA(Cg)缺失的谷氨酸棒杆菌的细胞两极，并恢复了极性肽聚糖合成。这证实了放线菌的DivIVA参与极化细胞生长。DivIVA(Cg)在细胞壁合成开始且类核已经分离后定位于隔膜处，这表明在谷氨酸棒杆菌中DivIVA不参与细胞分裂或染色体分离。
