title: Distinct pools of proliferating cell nuclear antigen associated to DNA replication sites interact with the p125 subunit of DNA polymerase delta or DNA ligase I.
abstract: Proliferating cell nuclear antigen (PCNA) plays an essential role in DNA replication, repair, and cell cycle control. PCNA is a homotrimeric ring that, when encircling DNA, is not easily extractable. Consequently, the dynamics of protein-protein interactions established by PCNA at DNA replication sites is not well understood. We have used DNase I to release DNA-bound PCNA together with replication proteins including the p125-catalytic subunit of DNA polymerase delta (p125-pol delta), DNA ligase I, cyclin A, and cyclin-dependent kinase 2 (CDK2). Interaction with these proteins was investigated by immunoprecipitation with antibodies binding near the interdomain connector loop or to the C-terminal domain of PCNA, respectively, or with antibodies to p125-pol delta or DNA ligase I. PCNA interaction with p125-pol delta or DNA ligase I was detected only by the latter antibodies, and found to be mutually exclusive. In contrast, antibodies to PCNA co-immunoprecipitated only CDK2. A GST-p21(waf1/cip1) C-terminal peptide displaced p125-pol delta and DNA ligase I, but not CDK2, from PCNA. These results suggest that PCNA trimers bound to DNA during the S phase are organized as distinct pools able to bind selectively different partners. Among them, p125-pol delta and DNA ligase I interact with PCNA in a mutually exclusive manner.
authors.affiliation: Istituto di Genetica Molecolare del CNR, Dipartimento di Biologia Animale, sezione Istochimica e Citometria, Università di Pavia, Piazza Botta 10, 27100 Pavia, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Riva
authors.forename: Monica
authors.initials: M
authors.lastname: Savio
authors.forename: Ornella
authors.initials: O
authors.lastname: Cazzalini
authors.forename: Lucia A
authors.initials: LA
authors.lastname: Stivala
authors.forename: Ivana A
authors.initials: IA
authors.lastname: Scovassi
authors.forename: Lynne S
authors.initials: LS
authors.lastname: Cox
authors.forename: Bernard
authors.initials: B
authors.lastname: Ducommun
authors.forename: Ennio
authors.initials: E
authors.lastname: Prosperi
mesh_terms: D000906:Antibodies / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites / Q000502:physiology; D042846:CDC2-CDC28 Kinases / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics*; D002460:Cell Line; D019925:Cyclin A / Q000235:genetics / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D004247:DNA / Q000378:metabolism*; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism*; D004258:DNA Polymerase III / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000235:genetics*; D003851:Deoxyribonucleases / Q000378:metabolism; D005333:Fetus; D006801:Humans; D010446:Peptide Fragments / Q000378:metabolism / Q000494:pharmacology; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000235:genetics
chemical_list: D000906:Antibodies; D019925:Cyclin A; C000607892:LIG1 protein, human; D010446:Peptide Fragments; D018809:Proliferating Cell Nuclear Antigen; D004247:DNA; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D004258:DNA Polymerase III; D003851:Deoxyribonucleases; D011088:DNA Ligases; D000072481:DNA Ligase ATP