title: p21WAF/CIP1/SDI1 is upregulated due to increased mRNA stability during hydroxyurea-induced senescence of human fibroblasts.
abstract: Hydoxyurea induces senescence-like growth arrest in normal human fibroblasts. p21(WAF/CIP1/SDI1), a cyclin dependent kinase inhibitor, was found to be upregulated during this growth arrest. Levels of p21(WAF/CIP1/SDI1) protein and mRNA were increased nine-fold by hydroxyurea in these cells. In order to determine whether p21(WAF/CIP1/SDI1) mRNA is increased by hydroxyurea at the transcriptional level, human fibroblast cells were transfected with reporter constructs containing a p21(WAF/CIP1/SDI1) promoter fragment and then treated with hydroxyurea. The luciferase activities in the reporter-transfected fibroblast cells were not increased by hydroxyurea, indicating that p21(WAF/CIP1/SDI1) transcription was not elevated by hydroxyurea. The half-life of the p21(WAF/CIP1/SDI1) mRNA was increased by 2.5-fold but that of p21(WAF/CIP1/SDI1) protein was not. Our results suggest that increased mRNA stability is the major mechanism of p21(WAF/CIP1/SDI1) elevation in the hydroxyurea-induced growth arrest of human fibroblasts.
authors.affiliation: Department of Biochemistry, College of Medicine, Hallym University, 1 Okchon-dong, Chuncheon, Gangwon-do 200-702, South Korea.
authors.forename: Hyun-Seok
authors.initials: HS
authors.lastname: Kim
authors.forename: Eui-ju
authors.initials: EJ
authors.lastname: Yeo
authors.forename: Seong-Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Joo-In
authors.initials: JI
authors.lastname: Park
authors.forename: Sang-Chul
authors.initials: SC
authors.lastname: Park
authors.forename: Jong-Yeon
authors.initials: JY
authors.lastname: Shin
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Kim
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Oh
authors.forename: Moo-Ho
authors.initials: MH
authors.lastname: Won
authors.forename: Tae-Chun
authors.initials: TC
authors.lastname: Kang
authors.forename: Jae-Bong
authors.initials: JB
authors.lastname: Park
authors.forename: Jaebong
authors.initials: J
authors.lastname: Kim
authors.forename: Jong-Il
authors.initials: JI
authors.lastname: Kim
authors.forename: Hyun-Yong
authors.initials: HY
authors.lastname: Lee
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Lee
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D016922:Cellular Senescence; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D006918:Hydroxyurea / Q000378:metabolism / Q000494:pharmacology*; D008156:Luciferases / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D012333:RNA, Messenger; D008156:Luciferases; D006918:Hydroxyurea