Involvement of the interaction between p21 and proliferating cell nuclear antigen for the maintenance of G2/M arrest after DNA damage.
Although a major effect of p21, a cyclin-dependent kinase inhibitor, is considered to be exerted during G(1) phase of the cell cycle, p21 gene knock-out studies suggested its involvement in G(2)/M checkpoint as well. Here we demonstrate evidence that p21 is required for the cell cycle arrest at G(2) upon DNA damage. We found that expression of wild-type p21 (p21(WT)), not mutant p21 (p21(PCNA-)) lacking the interaction with proliferating cell nuclear antigen (PCNA), caused G(2) cell cycle arrest in p53-deficient DLD1 colon cancer cell line after the DNA damage by treatment with cis-diamminedichloroplatinum (II). We also found that p21(WT) was associated with Cdc2/cyclin B1 together with PCNA. Furthermore, coimmunoprecipitation experiments revealed that PCNA interacted with Cdc25C at the G(2)/M transition, and this interaction was abolished when p21(WT) was expressed presumably due to the competition between p21(WT) and Cdc25C in the binding to PCNA. These findings suggest that p21 plays a regulatory role in the maintenance of cell cycle arrest at G(2) by blocking the interaction of Cdc25C with PCNA.
Ando
T
T
Department of Molecular Genetics and First Department of Internal Medicine, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
Kawabe
T
T
Ohara
H
H
Ducommun
B
B
Itoh
M
M
Okamoto
T
T
D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000494:pharmacology; D001667:Binding, Competitive; D015153:Blotting, Western; D002945:Cisplatin / Q000494:pharmacology; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology*; D004249:DNA Damage; D005434:Flow Cytometry; D016195:G2 Phase; D016158:Genes, p53 / Q000235:genetics; D006801:Humans; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D011233:Precipitin Tests; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D018809:Proliferating Cell Nuclear Antigen; D002945:Cisplatin