Friedrich Schiller University Jena, Institute of Microbiology, Jena, Germany.
Faculty of Biology I, Ludwig-Maximilians-University of Munich, Martinsried, Germany.
Elife. 2020 Aug 3;9:e58836. doi: 10.7554/eLife.58836.
Negative feedback regulation, that is the ability of a gene to repress its own synthesis, is the most abundant regulatory motif known to biology. Frequently reported for transcriptional regulators, negative feedback control relies on binding of a transcription factor to its own promoter. Here, we report a novel mechanism for gene autoregulation in bacteria relying on small regulatory RNA (sRNA) and the major endoribonuclease, RNase E. TIER-seq analysis (transiently-inactivating-an-endoribonuclease-followed-by-RNA-seq) revealed ~25,000 RNase E-dependent cleavage sites in , several of which resulted in the accumulation of stable sRNAs. Focusing on two examples, OppZ and CarZ, we discovered that these sRNAs are processed from the 3' untranslated region (3' UTR) of the and operons, respectively, and base-pair with their own transcripts to inhibit translation. For OppZ, this process also triggers Rho-dependent transcription termination. Our data show that sRNAs from 3' UTRs serve as autoregulatory elements allowing negative feedback control at the post-transcriptional level.
负反馈调节，即基因抑制自身合成的能力，是生物学中已知的最丰富的调节基序。转录调控因子经常报道负反馈控制依赖于转录因子与其自身启动子的结合。在这里，我们报告了一种细菌中基因自身调控的新机制，该机制依赖于小调控 RNA（sRNA）和主要内切核酸酶 RNase E。TIER-seq 分析（短暂失活内切核酸酶后进行 RNA-seq）在 中发现了约 25000 个依赖于 RNase E 的切割位点，其中几个导致稳定 sRNA 的积累。我们专注于两个例子，OppZ 和 CarZ，发现这些 sRNA 分别从 和 操纵子的 3'非翻译区（3'UTR）加工而来，并与自身转录本结合抑制翻译。对于 OppZ，这个过程还触发 Rho 依赖性转录终止。我们的数据表明，来自 3'UTR 的 sRNA 可作为自身调节元件，允许在转录后水平进行负反馈控制。
