The ithree Institute, University of Technology Sydney (UTS), Sydney NSW, Australia.
University of Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.
Dev Cell. 2021 Jan 11;56(1):36-51.e5. doi: 10.1016/j.devcel.2020.12.006. Epub 2020 Dec 30.
Asymmetric division, a hallmark of endospore development, generates two cells, a larger mother cell and a smaller forespore. Approximately 75% of the forespore chromosome must be translocated across the division septum into the forespore by the DNA translocase SpoIIIE. Asymmetric division also triggers cell-specific transcription, which initiates septal peptidoglycan remodeling involving synthetic and hydrolytic enzymes. How these processes are coordinated has remained a mystery. Using Bacillus subtilis, we identified factors that revealed the link between chromosome translocation and peptidoglycan remodeling. In cells lacking these factors, the asymmetric septum retracts, resulting in forespore cytoplasmic leakage and loss of DNA translocation. Importantly, these phenotypes depend on septal peptidoglycan hydrolysis. Our data support a model in which SpoIIIE is anchored at the edge of a septal pore, stabilized by newly synthesized peptidoglycan and protein-protein interactions across the septum. Together, these factors ensure coordination between chromosome translocation and septal peptidoglycan remodeling to maintain spore development.
不对称分裂是芽孢发育的一个标志，它产生两个细胞，一个较大的母细胞和一个较小的前孢子。大约 75%的前孢子染色体必须通过 DNA 转位酶 SpoIIIE 穿过分裂隔膜转移到前孢子中。不对称分裂还触发了细胞特异性转录，从而启动了涉及合成和水解酶的隔膜肽聚糖重塑。这些过程是如何协调的仍然是一个谜。我们使用枯草芽孢杆菌鉴定了一些因素，这些因素揭示了染色体易位和肽聚糖重塑之间的联系。在缺乏这些因素的细胞中，不对称隔膜回缩，导致前孢子细胞质泄漏和 DNA 易位丢失。重要的是，这些表型依赖于隔膜肽聚糖的水解。我们的数据支持这样一种模型，即 SpoIIIE 锚定在隔膜孔的边缘，由新合成的肽聚糖和跨隔膜的蛋白质-蛋白质相互作用稳定。这些因素共同确保了染色体易位和隔膜肽聚糖重塑之间的协调，以维持孢子发育。
