Source:http://linkedlifedata.com/resource/pubmed/id/11753641
Switch to
Predicate | Object |
---|---|
rdf:type | |
lifeskim:mentions | |
pubmed:issue |
52
|
pubmed:dateCreated |
2001-12-25
|
pubmed:abstractText |
The tumor suppressor protein p53 plays a critical role in the maintenance of genetic integrity. p53 possesses 3'-->5' exonuclease activity, however, the significance of this function in DNA replication process remains elusive. It was suggested that 3'-->5' exonuclease activity of p53 may provide a proofreading function for DNA polymerases. In order to better understand the significance of this activity, the purified wild-type recombinant p53 was further evaluated for substrate specificity and for contribution to the accuracy of DNA synthesis. p53-associated 3'-->5' exonuclease displays 3' terminal nucleotide excision from RNA/DNA template-primer using ribosomal RNA as a template. The data demonstrate that p53 is highly efficient in removing a terminal mispair. Analysis of mispair excision opposite the template adenine residue shows that p53 catalyzes 3' terminal mismatch excision with a specificity of A : G>A : A>A : C. Hence, the observed specificity of mismatch excision indicates that p53 exonucleolytic proofreading preferentially repairs transversion mutations. The influence of the p53 on the accuracy of DNA synthesis was determined with exonuclease-deficient human immunodeficiency virus-1 (HIV-1) reverse transcriptase (RT), a key enzyme in the life cycle of the virus, that contributes significantly to the low accuracy of proviral DNA synthesis. Using an in vitro biochemical assay with recombinant purified HIV-1 RT, p53 and defined RNA/DNA or DNA/DNA template-primers, two basic features related to fidelity of DNA synthesis were studied: the misinsertion and mispair extension. The misincorporation of non-complementary deoxynucleotides into nascent DNA and subsequent mispair extension by HIV-1 RT were substantially decreased in the presence of p53 with both RNA/DNA and DNA/DNA template-primers. In addition, the productive interaction between polymerization (by HIV-1 RT) and exonuclease (by p53) activities was observed; p53 preferentially hydrolyzes mispaired 3'-termini, permitting subsequent extension of the correctly paired 3'-terminus by HIV-1 RT. Taken together the data demonstrate that preferential excision of mismatched nucleotides by 3'-->5' exonuclease activity of wild-type p53 enhances the fidelity of DNA synthesis by HIV-1 RT in vitro, thus providing a biochemical mechanism to reduce mutations caused by incorporation of mismatched nucleotides. The fact that p53 is reactive with both RNA/DNA and DNA/DNA template-primers raises an interesting possibility of the existence of functional cooperation between p53 and HIV-1 RT in cytoplasm during the reverse transcription process, which may be important for maintaining HIV genomic integrity.
|
pubmed:language |
eng
|
pubmed:journal | |
pubmed:citationSubset |
IM
|
pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/DNA, Viral,
http://linkedlifedata.com/resource/pubmed/chemical/DNA Primers,
http://linkedlifedata.com/resource/pubmed/chemical/Exodeoxyribonuclease V,
http://linkedlifedata.com/resource/pubmed/chemical/Exodeoxyribonucleases,
http://linkedlifedata.com/resource/pubmed/chemical/HIV Reverse Transcriptase,
http://linkedlifedata.com/resource/pubmed/chemical/Nucleic Acid Heteroduplexes,
http://linkedlifedata.com/resource/pubmed/chemical/RNA,
http://linkedlifedata.com/resource/pubmed/chemical/RNA primers,
http://linkedlifedata.com/resource/pubmed/chemical/Tumor Suppressor Protein p53
|
pubmed:status |
MEDLINE
|
pubmed:month |
Nov
|
pubmed:issn |
0950-9232
|
pubmed:author | |
pubmed:issnType |
Print
|
pubmed:day |
15
|
pubmed:volume |
20
|
pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
7635-44
|
pubmed:dateRevised |
2007-11-15
|
pubmed:meshHeading |
pubmed-meshheading:11753641-Base Pair Mismatch,
pubmed-meshheading:11753641-DNA, Viral,
pubmed-meshheading:11753641-DNA Damage,
pubmed-meshheading:11753641-DNA Primers,
pubmed-meshheading:11753641-Exodeoxyribonuclease V,
pubmed-meshheading:11753641-Exodeoxyribonucleases,
pubmed-meshheading:11753641-HIV Reverse Transcriptase,
pubmed-meshheading:11753641-HIV-1,
pubmed-meshheading:11753641-Humans,
pubmed-meshheading:11753641-Nucleic Acid Heteroduplexes,
pubmed-meshheading:11753641-RNA,
pubmed-meshheading:11753641-Templates, Genetic,
pubmed-meshheading:11753641-Tumor Suppressor Protein p53
|
pubmed:year |
2001
|
pubmed:articleTitle |
p53 enhances the fidelity of DNA synthesis by human immunodeficiency virus type 1 reverse transcriptase.
|
pubmed:affiliation |
Infectious Diseases Unit, Chaim Sheba Medical Center, Tel Hashomer 52621, Israel. bakhanus@yahoo.com
|
pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|