a protein inventory of human ribosome biogenesis reveals an essential function of exportin 5 in 60s subunit export人类核糖体蛋白质库存生源论揭示了一个重要的功能在60年代间5单元出口.pdfVIP

A Protein Inventory of Human Ribosome Biogenesis Reveals an Essential Function of Exportin 5 in 60S Subunit Export 1,2 3 1,2 1,2 1,2 Thomas Wild , Peter Horvath , Emanuel Wyler , Barbara Widmann , Lukas Badertscher , Ivo 1 3 3 4 1 Zemp , Karol Kozak , Gabor Csucs , Elsebet Lund , Ulrike Kutay * 1 Institute of Biochemistry, ETH Zurich, Zurich, Switzerland, 2 Molecular Life Science Ph.D. Program, Zurich, Switzerland, 3 Light Microscopy Center, RISC, Department of Biology, ETH Zurich, Zurich, Switzerland, 4 University of Wisconsin, Madison, Wisconsin, United States of America Abstract The assembly of ribosomal subunits in eukaryotes is a complex, multistep process so far mostly studied in yeast. In S. cerevisiae, more than 200 factors including ribosomal proteins and trans-acting factors are required for the ordered assembly of 40S and 60S ribosomal subunits. To date, only few human homologs of these yeast ribosome synthesis factors have been characterized. Here, we used a systematic RNA interference (RNAi) approach to analyze the contribution of 464 candidate factors to ribosomal subunit biogenesis in human cells. The screen was based on visual readouts, using inducible, fluorescent ribosomal proteins as reporters. By performing computer-based image analysis utilizing supervised machine- learning techniques, we obtained evidence for a functional link of 153 human proteins to ribosome synthesis. Our data show that core features of ribosome assembly are conserved from yeast to human, but differences exist for instance with respect to 60S subunit export. Une