Replication protein A stimulates long patch DNA base excision repair.
Two pathways for completion of DNA base excision repair (BER) have recently emerged. In one, called short patch BER, only the damaged nucleotide is replaced, whereas in the second, known as long patch BER, the monobasic lesion is removed along with additional downstream nucleotides. Flap endonuclease 1, which preferentially cleaves unannealed 5'-flap structures in DNA, has been shown to play a crucial role in the long patch mode of repair. This nuclease will efficiently release 5'-terminal abasic lesions as part of an intact oligonucleotide when cleavage is combined with strand displacement synthesis. Further gap filling and ligation complete repair. We reconstituted the final steps of long patch base excision repair in vitro using calf DNA polymerase epsilon to provide strand displacement synthesis, human flap endonuclease 1, and human DNA ligase I. Replication protein A is an important constituent of the DNA replication machinery. It also has been shown to interact with an early component of base excision repair: uracil glycosylase. Here we show that human replication protein A greatly stimulates long patch base excision repair.
DeMott
M S
MS
Department of Biochemistry & Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
Zigman
S
S
Bambara
R A
RA
D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000378:metabolism; D004257:DNA Polymerase II / Q000378:metabolism; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000378:metabolism; D045585:Flap Endonucleases; D006801:Humans; D011189:Potassium Chloride / Q000494:pharmacology; D051716:Replication Protein A
D004268:DNA-Binding Proteins; C000607892:LIG1 protein, human; C497167:RPA1 protein, human; D051716:Replication Protein A; D011189:Potassium Chloride; D004257:DNA Polymerase II; D004706:Endodeoxyribonucleases; D045585:Flap Endonucleases; C468317:FEN1 protein, human; D011088:DNA Ligases; D000072481:DNA Ligase ATP