Regulation of mammalian ribonucleotide reductase R1 mRNA stability is mediated by a ribonucleotide reductase R1 mRNA 3'-untranslated region cis-trans interaction through a protein kinase C-controlled pathway.
Ribonucleotide reductase catalyses the reaction that eventually provides the four deoxyribonucleotides required for the synthesis and repair of DNA. U.v.-cross-linking and band-shift experiments have identified in COS 7 monkey cells an approx. 57 kDa ribonucleotide reductase R1 mRNA-binding protein called R1BP, which binds specifically to a 49-nt region of the R1 mRNA 3'-untranslated region (3'UTR). The R1BP-RNA binding activity was down-regulated by the tumour promoters phorbol 12-myristate 13-acetate (PMA; 'TPA') and okadaic acid, and up-regulated by the protein kinase C inhibitor staurosporine, in a dose-dependent fashion. Furthermore, staurosporine treatment decreased the stability of R1 and CAT (chloramphenicol acetyltransferase)/R1 hybrid mRNAs, whereas PMA and okadaic acid increased the stability of these messages, in a dose-dependent manner. In contrast, treatment of cells with forskolin, a protein kinase A inhibitor, did not alter either R1BP-RNA binding or R1 mRNA-stability characteristics. Transfectants containing R1 or CAT/R1 cDNA constructs with a deletion of the 49-nt 3'UTR sequence failed to respond in message-stability studies to the effects of PMA, staurosporine or okadaic acid. These observations indicate that a protein kinase C signal pathway regulates ribonucleotide reductase R1 gene expression post-transcriptionally, through a mechanism involving a specific cis-trans interaction at a 49-nt region within the R1 mRNA 3'UTR.
Chen
F Y
FY
Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada.
Amara
F M
FM
Wright
J A
JA
D016475:3T3 Cells; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004988:Ethers, Cyclic / Q000494:pharmacology; D000882:Haplorhini; D051379:Mice; D008807:Mice, Inbred BALB C; D019319:Okadaic Acid; D014176:Protein Biosynthesis; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012264:Ribonucleotide Reductases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D019311:Staurosporine
D000470:Alkaloids; D004988:Ethers, Cyclic; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D019319:Okadaic Acid; D012264:Ribonucleotide Reductases; D015500:Chloramphenicol O-Acetyltransferase; D011493:Protein Kinase C; D019311:Staurosporine