Studies on the interactions between human replication factor C and human proliferating cell nuclear antigen.
Proliferating cell nuclear antigen (PCNA) is a processivity factor required for DNA polymerase delta (or epsilon)-catalyzed DNA synthesis. When loaded onto primed DNA templates by replication factor C (RFC), PCNA acts to tether the polymerase to DNA, resulting in processive DNA chain elongation. In this report, we describe the identification of two separate peptide regions of human PCNA spanning amino acids 36-55 and 196-215 that bind RFC by using the surface plasmon resonance technique. Site-directed mutagenesis of residues within these regions in human PCNA identified two specific sites that affected the biological activity of PCNA. Replacement of the aspartate 41 residue by an alanine, serine, or asparagine significantly impaired the ability of PCNA to (i) support the RFC/PCNA-dependent polymerase delta-catalyzed elongation of a singly primed DNA template; (ii) stimulate RFC-catalyzed DNA-dependent hydrolysis of ATP; (iii) be loaded onto DNA by RFC; and (iv) activate RFC-independent polymerase delta-catalyzed synthesis of poly dT. Introduction of an alanine at position 210 in place of an arginine also reduced the efficiency of PCNA in supporting RFC-dependent polymerase delta-catalyzed elongation of a singly primed DNA template. However, this mutation did not significantly alter the ability of PCNA to stimulate DNA polymerase delta in the absence of RFC but substantially lowered the efficiency of RFC-catalyzed reactions. These results are in keeping with a model in which surface exposed regions of PCNA interact with RFC and the subsequent loading of PCNA onto DNA orients the elongation complex in a manner essential for processive DNA synthesis.
Program in Molecular Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue/Box 97, New York, NY 10021, USA.
G
G
Zhang
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E
Gibbs
Z
Z
Kelman
M
M
O'Donnell
J
J
Hurwitz
D019943:Amino Acid Substitution; D004258:DNA Polymerase III / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D018398:Homeodomain Proteins; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D015778:Minor Histocompatibility Antigens; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry; D010957:Plasmids; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D051818:Replication Protein C; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins
C096816:BCL2-related protein A1; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C096063:MATA1 protein, S cerevisiae; D046911:Macromolecular Substances; D015778:Minor Histocompatibility Antigens; D010446:Peptide Fragments; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; C497561:RFC2 protein, human; C497562:RFC3 protein, human; C497563:RFC4 protein, human; C497564:RFC5 protein, human; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D004258:DNA Polymerase III; D051818:Replication Protein C