Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function
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The Ohio State University / OhioLINK
2005
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu11176561582021-08-03T05:50:01Z Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function Lamarche, Brandon James African swine fever virus DNA repair error-prone DNA ligase mutagenesis <p>The African Swine Fever Virus (ASFV) is a cytoplasmic DNA virus that causes a potentially lethal disease in domestic pigs. Antigenic differences among field isolates indicate that ASFV exists as a diverse population of serotypes in some regions of Africa, and restriction fragment length polymorphisms suggest that this diversity may arise from point mutations.</p><p>Consistent with its intracellular location, ASFV encodes three DNA repair proteins: a polymerase, an AP endonuclease, and a DNA ligase. The ASFV repair polymerase, Pol X, is extremely error-prone during single nucleotide gap filling, leading others to hypothesize that it might contribute to the genetic variability of ASFV. However, in order for the error-proneness of Pol X to be biologically relevant it would need to function within a repair system in which each of the components tolerated and/or utilized the mismatched intermediates and products being generated. The work described herein was undertaken to assess whether such a system exists.</p><p>We demonstrate that ASFV gene <i>E296R</i> is an AP endonuclease, a 3’-phosphodiesterase, and a 3’→5 exonuclease. Pol X and ASFV DNA ligase are both shown to contribute lyase activity towards 5’-2-deoxyribose-5-phosphate.</p><p>Having established a complete viral abasic site repair system, we subsequently assess its capacity for mutagenesis. The catalytic efficiency of nick sealing by ASFV DNA ligase is determined for substrates containing all 16 possible base pair combinations at the 3’ side of a nick. Our results indicate this enzyme to be the lowest fidelity DNA ligase ever reported – capable of ligating a 3’ mismatched nick more efficiently than nicks containing Watson-Crick base pairs. Comparison of the mismatch specificity of Pol X with that of ASFV DNA ligase suggests that the latter may have evolved towards low fidelity for the purpose of generating the broadest possible spectrum of sealed mismatches. In competition experiments where mismatched nicks are incubated with both ASFV DNA ligase and ASFV AP endonuclease, the ligation activity competes very effectively with the 3’→5’ exonuclease editing activity – supporting the hypothesis that error-prone repair of the ASFV genome may facilitate its diversification.</p> 2005-08-04 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1117656158 http://rave.ohiolink.edu/etdc/view?acc_num=osu1117656158 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
African swine fever virus DNA repair error-prone DNA ligase mutagenesis |
| spellingShingle |
African swine fever virus DNA repair error-prone DNA ligase mutagenesis Lamarche, Brandon James Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| author |
Lamarche, Brandon James |
| author_facet |
Lamarche, Brandon James |
| author_sort |
Lamarche, Brandon James |
| title |
Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| title_short |
Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| title_full |
Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| title_fullStr |
Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| title_full_unstemmed |
Error-prone DNA repair in the African swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| title_sort |
error-prone dna repair in the african swine fever virus: characterization of six abasic site processing activities and evidence for a mutagenic function |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2005 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1117656158 |
| work_keys_str_mv |
AT lamarchebrandonjames errorpronednarepairintheafricanswinefeverviruscharacterizationofsixabasicsiteprocessingactivitiesandevidenceforamutagenicfunction |
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