A single amino acid change (E85K) in human PCNA that leads, relative to wild type, to enhanced DNA synthesis by DNA polymerase delta past nucleotide base lesions (TLS) as well as on unmodified templates.
Human proliferating cell nuclear antigen (hPCNA) containing a single amino acid substitution at position 85, that of lysine for glutamate (E85K), was compared to wild-type (wt) hPCNA for its ability to promote DNA synthesis by purified DNA polymerase delta (pol delta) both on unmodified templates and past chemically defined template base lesions (translesion synthesis; TLS). Significant enhancement (up to 4-5-fold or greater) was seen but depended both on the exact PCNA/pol delta ratio tested and on the specific nature of the template (e.g., unmodified versus lesion-containing; chemical nature of the template base lesion). These results suggest that human PCNA, either mutated to contain lysine (K) at position 85 or bearing similar primary mutations, would promote more secondary mutagenesis in cells and/or tissues where PCNA is normally expressed at low levels relative to pol delta. Over an entire lifetime, such secondary mutagenesis could be biomedically significant.
Fisher
Paul A
PA
Department of Pharmacological Sciences, University Medical Center, State University of New York, Stony Brook, New York 11794-8651, USA. paul@pharm.sunysb.edu
Moutsiakis
Demetrius L
DL
McConnell
Maeve
M
Miller
Holly
H
Mozzherin
Dmitry Ju
DJ
D019943:Amino Acid Substitution; D004249:DNA Damage; D004258:DNA Polymerase III / Q000378:metabolism / Q000502:physiology*; D004261:DNA Replication; D018698:Glutamic Acid / Q000235:genetics; D006801:Humans; D008239:Lysine / Q000235:genetics; D016296:Mutagenesis; D017354:Point Mutation / Q000235:genetics; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics* / Q000378:metabolism; D013698:Templates, Genetic
D018809:Proliferating Cell Nuclear Antigen; D018698:Glutamic Acid; D004258:DNA Polymerase III; D008239:Lysine