ppGpp and Polyphosphate Modulate Cell Cycle Progression in Caulobacter crescentus
ppGpp and Polyphosphate Modulate Cell Cycle Progression in Caulobacter crescentus
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DOI：
10.1128/jb.05932-11
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发表时间：
2012-01-01
影响因子：
3.2
通讯作者：
Crosson, Sean
中科院分区：
文献类型：
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作者：
Boutte, Cara C.;Henry, Jonathan T.;Crosson, Sean
新月柄杆菌在其细胞周期中从活动的、觅食的群细胞分化为无柄的、具有复制能力的有柄细胞。这种发育转变受到营养剥夺的抑制，有利于运动的集群状态。我们确定了两种细胞周期调节信号，ppGpp 和多磷酸盐 (polyP)，它们在复杂和葡萄糖耗尽的培养基中抑制群细胞到茎状细胞的转变，从而增加混合培养物中群细胞的比例。当可用碳耗尽时，缺乏合成 ppGpp 或 polyP 能力的集群细胞会不正确地启动染色体复制，蛋白水解复制抑制剂 CtrA，定位细胞命运决定因子 DivJ，并形成极茎。此外，我们发现，在饥饿时，集群细胞比跟踪细胞产生更多的 ppGpp。这些结果证明 ppGpp 和 polyP 是细胞类型特异性的发育调节因子。
Caulobacter crescentus differentiates from a motile, foraging swarmer cell into a sessile, replication-competent stalked cell during its cell cycle. This developmental transition is inhibited by nutrient deprivation to favor the motile swarmer state. We identify two cell cycle regulatory signals, ppGpp and polyphosphate (polyP), that inhibit the swarmer-to-stalked transition in both complex and glucose-exhausted media, thereby increasing the proportion of swarmer cells in mixed culture. Upon depletion of available carbon, swarmer cells lacking the ability to synthesize ppGpp or polyP improperly initiate chromosome replication, proteolyze the replication inhibitor CtrA, localize the cell fate determinant DivJ, and develop polar stalks. Furthermore, we show that swarmer cells produce more ppGpp than stalked cells upon starvation. These results provide evidence that ppGpp and polyP are cell-type-specific developmental regulators.