title: Turnover of polyadenylated messenger RNA in fission yeast. Evidence for the control of protein synthesis at the translational level.
abstract: Polyadenylated RNA was isolated from fission yeast (Schizosaccharomyces pombe) total RNA using oligo(dT)-cellulose, and was studied as a model for messenger RNA. The half-life of poly adenylated RNA was measured by two independent methods. (a) The rate of labelling of polyadenylated RNA during incubation of cells with [5-3H]uridine was measured. A half-life of 40-45 min was found by comparing the experimental data with theoretical curves calculated for labelling of RNAs with various half-lives. The influence of precursor-pool specific activity on RNA labelling kinetics is considered. (b) Cells were labelled with [5-3H]uridine then further RNA synthesis was inhibited by addition of 8-hydroxyquinoline. The rate of loos of radioactivity from polyadenylated RNA indicated a half-life of 50 min. The half-life found by these two methods is about one-third of the cell doubling time, and is much longer than previous estimates by indirect methods of yeast messenger RNA half-life. Both experimental methods provided evidence for the existence of tas a half-life of 40-50 min; a much smaller population is probably turning over more rapidly. After inhibition of RNA synthesis by 8-hydroxyquinoline, the rate of total protein synthesis declined much more rapidly than the polyadenylated RNA content of the cells. However, 60 min after inhibition of RNA synthesis there was a small rise in the rate of portein synthesis. These data are interpreted as evidence for mechanisms controlling protein synthesis which operate at the level of messenger RNA translation.
mesh_terms: D001203:Ascomycota / Q000378:metabolism*; D002846:Chromatography, Affinity; D005656:Fungal Proteins / Q000096:biosynthesis; D006207:Half-Life; D007700:Kinetics; D011061:Poly A / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism*; D004718:Saccharomycetales / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger; D011061:Poly A