title: Complementation of aprataxin deficiency by base excision repair enzymes.
abstract: Abortive ligation during base excision repair (BER) leads to blocked repair intermediates containing a 5'-adenylated-deoxyribose phosphate (5'-AMP-dRP) group. Aprataxin (APTX) is able to remove the AMP group allowing repair to proceed. Earlier results had indicated that purified DNA polymerase β (pol β) removes the entire 5'-AMP-dRP group through its lyase activity and flap endonuclease 1 (FEN1) excises the 5'-AMP-dRP group along with one or two nucleotides. Here, using cell extracts from APTX-deficient cell lines, human Ataxia with Oculomotor Apraxia Type 1 (AOA1) and DT40 chicken B cell, we found that pol β and FEN1 enzymatic activities were prominent and strong enough to complement APTX deficiency. In addition, pol β, APTX and FEN1 coordinate with each other in processing of the 5'-adenylated dRP-containing BER intermediate. Finally, other DNA polymerases and a repair factor with dRP lyase activity (pol λ, pol ι, pol θ and Ku70) were found to remove the 5'-adenylated-dRP group from the BER intermediate. However, the activities of these enzymes were weak compared with those of pol β and FEN1.
authors: Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
authors: Melike
authors: M
authors: Çağlayan
authors: Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
authors: Julie K
authors: JK
authors: Horton
authors: Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
authors: Rajendra
authors: R
authors: Prasad
authors: Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA wilson5@niehs.nih.gov.
authors: Samuel H
authors: SH
authors: Wilson
mesh_terms: D000249:Adenosine Monophosphate / Q000378:metabolism; D000818:Animals; D002457:Cell Extracts; D002460:Cell Line; D002645:Chickens; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D045585:Flap Endonucleases / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D017353:Gene Deletion; D006801:Humans; D051379:Mice; D009687:Nuclear Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
chemical_list: C438188:APTX protein, human; D002457:Cell Extracts; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000249:Adenosine Monophosphate; D019951:DNA Polymerase beta; D045585:Flap Endonucleases; D045643:DNA Repair Enzymes