An RNasin-resistant ribonuclease selective for interleukin 2 mRNA.
Interleukin 2 (IL2) mRNA has a short half-life in the cytoplasm of T lymphocytes, relative to most mRNA. We have discovered a candidate ribonuclease to account for the rapid turnover of IL2 mRNA in the cytosol of the human T lymphocyte cell line Jurkat. In partially purified form, this RNase is about 7 times as active on IL2 as on beta-globin mRNA. Pancreatic RNase, by contrast, does not show a significant preference for IL2 mRNA. Neither 5' capping, nor polyadenylation of the substrate mRNAs affects their degradation by the IL2-selective mRNase, whose activity is optimal in 0.5 mM Mg++ and 100 mM potassium acetate. The mRNase behaves like a protein of molecular weight 60-70,000 on gel chromatography, and is unusual in that it is insensitive to placental RNase inhibitor (RNasin). The mRNase cleaves IL2 mRNA at a small number of sites in the coding region, and IL2 mRNA containing only the coding region and 36 nucleotides of the 3'-noncoding region competes efficiently with full-length IL2 mRNA for the mRNase, whereas beta-globin mRNA does not.
Hua
J
J
Department of Biochemistry, University of Alberta, Edmonton, Canada.
Garner
R
R
Paetkau
V
V
D001483:Base Sequence; D002460:Cell Line; D002850:Chromatography, Gel; D004247:DNA; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D007938:Leukemia; D008969:Molecular Sequence Data; D010926:Placental Hormones / Q000378:metabolism; D011061:Poly A / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012260:Ribonucleases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D007376:Interleukin-2; D010926:Placental Hormones; D012333:RNA, Messenger; C022052:placental ribonuclease inhibitor; D011061:Poly A; D004247:DNA; D012260:Ribonucleases