Condensins are essential for global chromosome organization in diverse bacteria. Atypically, the Pseudomonas aeruginosa chromosome encodes condensins from two superfamilies, SMC-ScpAB and MksBEF. Here, we report that the two proteins play specialized roles in chromosome packing and segregation and are synthetically lethal with ParB. Inactivation of SMC or MksB affected, in a protein-dependent manner, global chromosome layout and its timing of segregation and sometimes triggered a chromosomal inversion. The localization pattern was also unique to each protein. SMC clusters colocalized with oriC throughout the cell cycle except shortly after origin duplication, whereas MksB clusters emerged at cell quarters shortly prior to oriC duplication and stayed there even after cell division. The relocation of the proteins was abrupt and coordinated with oriC dynamic. These data reveal that the two condensins play distinct dual roles in chromosome maintenance by organizing it and mediating its segregation. Furthermore, the choreography of condensins and oriC relocations suggest an elegant mechanism for the birth and maturation of chromosomes.

中文翻译：

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oriC，SMC和MksBEF在铜绿假单胞菌染色体分离中的交替动力学。

凝集素对于多种细菌中的全球染色体组织至关重要。非典型地，铜绿假单胞菌染色体编码来自SMC-ScpAB和MksBEF这两个超家族的凝缩蛋白。在这里，我们报道这两种蛋白质在染色体包装和分离中起专门作用，并且与ParB合成致死。SMC或MksB的失活以蛋白质依赖性方式影响整体染色体布局及其分离时间，有时还引发染色体倒置。定位模式对于每种蛋白质也是独特的。SMC簇在整个细胞周期中与oriC共定位，除非起源复制后不久，而MksB簇在oriC之前不久出现在细胞处复制并即使在细胞分裂后也呆在那里。蛋白质的重新定位突然发生并与oriC动态协调。这些数据表明，两个凝缩蛋白通过组织和介导其分离，在染色体维持中起着独特的双重作用。此外，凝缩蛋白的编排和oriC的重新定位为染色体的诞生和成熟提供了一种优雅的机制。