Đang chuẩn bị liên kết để tải về tài liệu:
Báo cáo y học: "The ribosomal subunit assembly line"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: The ribosomal subunit assembly line. | Minireview The ribosomal subunit assembly line Mensur Dlakic Address Department of Microbiology Montana State University Bozeman MT 59717 USA. E-mail mdlakic@montana.edu Published 19 September 2005 Genome Biology 2005 6 234 doi l0.ll86 gb-2005-6-l0-234 The electronic version of this article is the complete one and can be found online at http genomebiology.com 2005 6 10 234 2005 BioMed Central Ltd Abstract Recent proteomic studies in Saccharomyces cerevisiae have identified nearly 200 proteins other than the structural ribosomal proteins that participate in the assembly of ribosomal subunits and their transport from the nucleus. In a separate line of research proteomic studies of mature plant ribosomes have revealed considerable variability in the protein composition of individual ribosomes. The synthesis of ribosomes is a major metabolic task in eukaryotic cells. Transcription of all the genes involved requires the coordinated activities of all three RNA polymerases and consumes more than half of the cellular resources allocated to transcription 1 . Although eukaryotic ribosomes are composed of only four ribosomal RNAs rRNAs and around 80 ribosomal proteins many other proteins are recruited to help deliver ribosomal subunits to the cytoplasm - at the rate of 2 000 or so ribosomes each minute in a growing yeast cell for example 2 3 . In the past five years the extensive use of tandem affinity purification TAP of tagged proteins 4 has provided a detailed inventory of nearly 200 auxiliary proteins associated with pre-ribosomal particles 5-7 . These auxiliary proteins include RNases RNA-modification and -remodeling enzymes transport factors and many others whose function is unclear at present. In addition the protein content of eukaryotic ribosomes has been determined in several proteomics studies revealing an unexpected variability from ribosome to ribosome that stems from the presence of ribosomal protein isoforms and their post-translational modifications 8 9 . .