Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
FEBS J. 2022 Jul;289(13):3630-3641. doi: 10.1111/febs.15904. Epub 2021 May 11.
Coordination of transcription and processing of RNA is a basic principle in regulation of gene expression in eukaryotes. In the case of mRNA, coordination is primarily founded on a co-transcriptional processing mechanism by which a nascent precursor mRNA undergoes maturation via cleavage and modification by the transcription machinery. A similar mechanism controls the biosynthesis of rRNA. However, the coordination of transcription and processing of tRNA, a rather short transcript, remains unknown. Here, we present a model for high molecular weight initiation complexes of human RNA polymerase III that assemble on tRNA genes and process precursor transcripts to mature forms. These multifunctional initiation complexes may support co-transcriptional processing, such as the removal of the 5' leader of precursor tRNA by RNase P. Based on this model, maturation of tRNA is predetermined prior to transcription initiation.
RNA 的转录和加工的协调是真核生物基因表达调控的一个基本原则。在信使 RNA 的情况下，协调主要是基于一个共转录加工机制，其中一个新生的前体 mRNA 通过转录机制的切割和修饰而成熟。类似的机制控制 rRNA 的生物合成。然而，tRNA 的转录和加工的协调，一个相当短的转录物，仍然未知。在这里，我们提出了一个人类 RNA 聚合酶 III 的高分子量起始复合物的模型，该复合物组装在 tRNA 基因上，并将前体转录物加工成成熟形式。这些多功能起始复合物可能支持共转录加工，如 RNase P 去除前体 tRNA 的 5' 引导序列。基于这个模型，tRNA 的成熟是在转录起始之前预先确定的。
