All eukaryotic mRNAs are capped at their 5＇ end. Capping of mRNAs takes place co-transcriptionally and involves three steps. The intermediates of the capping process, as well as the uncapped 5＇ tri-phosphate RNA, ar...All eukaryotic mRNAs are capped at their 5＇ end. Capping of mRNAs takes place co-transcriptionally and involves three steps. The intermediates of the capping process, as well as the uncapped 5＇ tri-phosphate RNA, are resistant to decapping and degradation by known factors, leading to the assumption that the capping process always proceeds to completion. This view was recently drastically changed. A novel family of enzymes, including the yeast proteins Rail, Dxo1/Ydr370C, and the mammalian protein DXO/Dom3Z, has been identified. These enzymes catalyze the conversion of the improperly capped mRNAs to 5＇ mono-phosphate RNA, allowing them to be degraded by 5＇-3＇ exoribonucleases. Several of these enzymes also possess 5＇-3＇ exoribonuclease activities themselves, and can single-handedly clear the improperly capped mRNAs. Studying of these enzymes has led to the realization that mRNA capping does not always proceed to completion, and the identification of an mRNA capping quality control mechanism in eukaryotes. In this paper, we briefly review recent advances in this area.展开更多
Eukaryotic gene expression is controlled by different levels of biological events, such as transcription factors regulating the timing and strength of transcripts production, alteration of transcription rate by RNA pr...Eukaryotic gene expression is controlled by different levels of biological events, such as transcription factors regulating the timing and strength of transcripts production, alteration of transcription rate by RNA processing, and mRNA stability during RNA processing and translation. RNAs, especially mRNAs, are relatively vulnerable molecules in living cells for ribonucleases （RNases）. The maintenance of quality and quantity of transcripts is a key issue for many biological processes. Extensive studies draw the conclusion that the stability of RNAs is dedicated-regulated, occurring co- and post-transcriptionally, and translation-coupled as well, either in the nucleus or cytoplasm. Recently, RNA stability in the nucleus has aroused much research interest, especially the stability of newly-made transcripts. In this article, we summarize recent progresses on mRNA stability in the nucleus, especially focusing on quality control of newly-made RNA by RNA polymerase Ⅱ in eukaryotes.展开更多
基金Project supported by the National Basic Research Program (973) of China (Nos.2011CB910500 and 2010CB912502)the One Hundred Talent Program of the Chinese Academy of Sciences,China
文摘All eukaryotic mRNAs are capped at their 5＇ end. Capping of mRNAs takes place co-transcriptionally and involves three steps. The intermediates of the capping process, as well as the uncapped 5＇ tri-phosphate RNA, are resistant to decapping and degradation by known factors, leading to the assumption that the capping process always proceeds to completion. This view was recently drastically changed. A novel family of enzymes, including the yeast proteins Rail, Dxo1/Ydr370C, and the mammalian protein DXO/Dom3Z, has been identified. These enzymes catalyze the conversion of the improperly capped mRNAs to 5＇ mono-phosphate RNA, allowing them to be degraded by 5＇-3＇ exoribonucleases. Several of these enzymes also possess 5＇-3＇ exoribonuclease activities themselves, and can single-handedly clear the improperly capped mRNAs. Studying of these enzymes has led to the realization that mRNA capping does not always proceed to completion, and the identification of an mRNA capping quality control mechanism in eukaryotes. In this paper, we briefly review recent advances in this area.
基金Project supported by the Talented Scientist Program from South China Agricultural University (No.4600-K14013)the National Natural Science Foundation of China (No.81301901)
文摘Eukaryotic gene expression is controlled by different levels of biological events, such as transcription factors regulating the timing and strength of transcripts production, alteration of transcription rate by RNA processing, and mRNA stability during RNA processing and translation. RNAs, especially mRNAs, are relatively vulnerable molecules in living cells for ribonucleases （RNases）. The maintenance of quality and quantity of transcripts is a key issue for many biological processes. Extensive studies draw the conclusion that the stability of RNAs is dedicated-regulated, occurring co- and post-transcriptionally, and translation-coupled as well, either in the nucleus or cytoplasm. Recently, RNA stability in the nucleus has aroused much research interest, especially the stability of newly-made transcripts. In this article, we summarize recent progresses on mRNA stability in the nucleus, especially focusing on quality control of newly-made RNA by RNA polymerase Ⅱ in eukaryotes.
