Assembly of DNA polymerase delta and epsilon holoenzymes depends on the geometry of the DNA template.
To study in details the assembly of DNA polymerases delta and epsilon holoenzymes a circular double-stranded DNA template containing a gap of 45 nucleotides was constructed. Both replication factor C and proliferating cell nuclear antigen were absolutely required and sufficient for assembly of DNA polymerase delta holoenzyme complex on DNA. On such a circular DNA substrate replication protein A (or E. coli single-strand DNA binding protein) was neither required for assembly of DNA polymerase delta holoenzyme complex nor for the gap-filling reaction. A circular structure of the DNA substrate was found to be absolutely critical for the ability of auxiliary proteins to interact with DNA polymerases. The linearization of the circular DNA template resulted in three dramatic effects: (i) DNA synthesis by DNA polymerase delta holoenzyme was abolished, (ii) the inhibition effect of replication factor C and proliferating cell nuclear antigen on DNA polymerase alpha was relieved and (iii) DNA polymerase epsilon could not form any longer a holoenzyme with replication factor C and proliferating cell nuclear antigen. The comparison of the effect of replication factor C and proliferating cell nuclear antigen on DNA polymerases alpha, delta and epsilon indicated that the auxiliary proteins appear to form a mobile clamp, which can easily slide along double-stranded DNA.
Podust
L M
LM
Department of Veterinary Biochemistry, University Zürich-Irchel, Switzerland.
Podust
V N
VN
Floth
C
C
Hübscher
U
U
D000818:Animals; D002417:Cattle; D004247:DNA / Q000096:biosynthesis; D004257:DNA Polymerase II / Q000378:metabolism; D004258:DNA Polymerase III; D004261:DNA Replication; D004270:DNA, Circular / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000494:pharmacology; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry*; D004926:Escherichia coli; D018398:Homeodomain Proteins; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D051716:Replication Protein A; D051818:Replication Protein C; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D013698:Templates, Genetic
C096816:BCL2-related protein A1; D004270:DNA, Circular; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C096063:MATA1 protein, S cerevisiae; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D051716:Replication Protein A; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; D004257:DNA Polymerase II; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D051818:Replication Protein C