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Functional sites of human PCNA which interact with p21 (Cip1/Waf1), DNA polymerase δ and replication factor C
Author(s) -
Oku Takashi,
Ikeda Soichiro,
Sasaki Hisashi,
Fukuda Kotaro,
Morioka Hiroshi,
Ohtsuka Eiko,
Yoshikawa Hiroshi,
Tsurimoto Toshiki
Publication year - 1998
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.1998.00199.x
Subject(s) - replication factor c , dna polymerase delta , proliferating cell nuclear antigen , biology , dna replication , dna polymerase , dna clamp , processivity , microbiology and biotechnology , dna polymerase ii , eukaryotic dna replication , replication protein a , dna , control of chromosome duplication , dna binding protein , genetics , gene , polymerase chain reaction , transcription factor , reverse transcriptase
Background: PCNA, an eukaryotic DNA sliding clamp interacts with replication factors and the cell cycle protein, p21(Cip1/Waf1) and functions as a molecular switch for DNA elongation. To understand how DNA replication is regulated through PCNA, elucidation of the precise mechanisms of these protein interactions is necessary. Results: Loop‐region mutants in which human PCNA sequences were substituted with the corresponding Saccharomyces cerevisiae PCNA regions were prepared. Analysis of their functions, along with previously prepared alanine scanning mutants, demonstrated that some loops interact with DNA polymerase δ (pol δ) and replication factor C (RFC). The p21 binding sites of PCNA, mapped by affinity measurement of the mutant forms, found to be located within a distinct structure of the PCNA monomer, overlap with RFC‐ and pol δ‐interaction sites. Competition between p21 and pol δ or RFC for binding to PCNA results in efficient inhibition of its stimulation of pol δ DNA synthesis and RFC ATPase but not of PCNA loading on DNA by RFC. Conclusions: Semi‐saturated amounts of p21 selectively block formation of the active pol δ complex but not the RFC–PCNA complex at 3′‐ends of DNA primers. This differential effect may explain the specific inhibition of DNA replication by p21.