tailieunhanh - Báo cáo y học: "Composition and conservation of the mRNA-degrading machinery in bacteria"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Composition and conservation of the mRNA-degrading machinery in bacteria | Kaberdin et al. Journal of Biomedical Science 2011 18 23 http content 18 1 23 The cost of publication in Journal of Biomedical Science Is borne by the National Science Council Taiwan JOURNAL OF BIOMEDICAL SCIENCE REVIEW Open Access Composition and conservation of the mRNA-degrading machinery in bacteria Vladimir R Kaberdin1 2 3 3 Dharam Singh13 and Sue Lin-Chao1 Abstract RNA synthesis and decay counteract each other and therefore inversely regulate gene expression in pro- and eukaryotic cells by controlling the steady-state level of individual transcripts. Genetic and biochemical data together with recent in depth annotation of bacterial genomes indicate that many components of the bacterial RNA decay machinery are evolutionarily conserved and that their functional analogues exist in organisms belonging to all kingdoms of life. Here we briefly review biological functions of essential enzymes their evolutionary conservation and multienzyme complexes that are involved in mRNA decay in Escherichia coli and discuss their conservation in evolutionarily distant bacteria. 1. mRNA turnover and its role in gene expression In contrast to metabolically stable DNA serving as a storehouse of genetic information the fraction of total RNA that delivers coding information to the proteinsynthesizing machinery . mRNA is intrinsically labile and continuously synthesized. The steady-state level of mRNA is tightly controlled enabling bacteria to selectively copy transcribe and decode genetic information pertinent to a particular physiological state Figure 1 . Since the steady-state level of mRNA can vary and is a function of RNA synthesis and decay the control of mRNA stability plays an essential role in the regulation of gene expression. As transcription and translation are coupled in bacteria the degree of their coupling can control the access of individual transcripts to the RNA decay machinery thus influencing the rate of mRNA turnover. For more .