Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, P.O.B. 12272, 9112001 Jerusalem, Israel.
Info-CORE, Bioinformatics Unit of the I-CORE Computation Center at the Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
Mol Cell. 2023 Nov 16;83(22):4158-4173.e7. doi: 10.1016/j.molcel.2023.10.010. Epub 2023 Nov 9.
Sporulating bacteria can retreat into long-lasting dormant spores that preserve the capacity to germinate when propitious. However, how the revival transcriptional program is memorized for years remains elusive. We revealed that in dormant spores, core RNA polymerase (RNAP) resides in a central chromosomal domain, where it remains bound to a subset of intergenic promoter regions. These regions regulate genes encoding for most essential cellular functions, such as rRNAs and tRNAs. Upon awakening, RNAP recruits key transcriptional components, including sigma factor, and progresses to express the adjacent downstream genes. Mutants devoid of spore DNA-compacting proteins exhibit scattered RNAP localization and subsequently disordered firing of gene expression during germination. Accordingly, we propose that the spore chromosome is structured to preserve the transcriptional program by halting RNAP, prepared to execute transcription at the auspicious time. Such a mechanism may sustain long-term transcriptional programs in diverse organisms displaying a quiescent life form.
产芽孢细菌可以退回到持久的休眠芽孢中，在有利条件下保持发芽的能力。然而，复苏转录程序是如何被多年记忆的仍然难以捉摸。我们发现，在休眠芽孢中，核心 RNA 聚合酶（RNAP）位于一个中央染色体区域，在那里它仍然与一组基因间启动子区域结合。这些区域调控编码大多数基本细胞功能的基因，如 rRNA 和 tRNA。在苏醒时，RNAP 招募关键转录成分，包括 sigma 因子，并前进表达相邻的下游基因。缺乏芽孢 DNA 压缩蛋白的突变体表现出分散的 RNAP 定位，随后在发芽过程中基因表达的无序发射。因此，我们提出，芽孢染色体的结构通过阻止 RNA 聚合酶来保存转录程序，为有利时机的转录做好准备。这种机制可能在表现出静止生命形式的各种生物体中维持长期的转录程序。
