Korobeinikova Anna, Laalami Soumaya, Berthy Clément, Putzer Harald
Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, CNRS, Université Paris Cité, 75005 Paris, France.
Inovarion, 75005 Paris, France.
Microorganisms. 2023 May 24;11(6):1374. doi: 10.3390/microorganisms11061374.
The instability of messenger RNA is crucial to the control of gene expression. In , RNase Y is the major decay-initiating endoribonuclease. Here, we show how this key enzyme regulates its own synthesis by modulating the longevity of its mRNA. Autoregulation is achieved through cleavages in two regions of the (RNase Y) transcript: (i) within the first ~100 nucleotides of the open reading frame, immediately inactivating the mRNA for further rounds of translation; (ii) cleavages in the 5' UTR, primarily within the 5'-terminal 50 nucleotides, creating entry sites for the 5' exonuclease J1 whose progression is blocked around position -15 of the mRNA, potentially by initiating ribosomes. This links the functional inactivation of the transcript by RNase J1 to translation efficiency, depending on the ribosome occupancy at the translation initiation site. By these mechanisms, RNase Y can initiate degradation of its own mRNA when the enzyme is not occupied with degradation of other RNAs and thus prevent its overexpression beyond the needs of RNA metabolism.
信使核糖核酸的不稳定性对于基因表达的调控至关重要。在[具体生物或系统]中，核糖核酸酶Y是主要的引发衰变的核糖核酸内切酶。在此，我们展示了这种关键酶如何通过调节其信使核糖核酸的寿命来调控自身的合成。自我调控是通过在[核糖核酸酶Y]转录本的两个区域进行切割来实现的：（i）在开放阅读框的前约100个核苷酸内，立即使信使核糖核酸失活，无法进行进一步的翻译循环；（ii）在5'非翻译区进行切割，主要在5'末端的50个核苷酸内，为5'核酸外切酶J1创造进入位点，J1的进程在[核糖核酸酶Y]信使核糖核酸的大约-15位置处受阻，可能是被起始核糖体所阻碍。这将核糖核酸酶J1对转录本的功能性失活与翻译效率联系起来，具体取决于翻译起始位点处的核糖体占据情况。通过这些机制，当该酶没有忙于其他核糖核酸的降解时，核糖核酸酶Y可以启动自身信使核糖核酸的降解，从而防止其表达超过核糖核酸代谢的需求而过度表达。
