Linked Life Data

8028006

Source:http://linkedlifedata.com/resource/pubmed/id/8028006

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1994-8-9
pubmed:abstractText
In order to study the conversion of UV lesions into frameshift and base substitution mutations, M13mp2 phage DNA was altered by the addition of extra pyrimidines, or by construction of a nonsense codon preceded by a run of pyrimidines within the beta-galactosidase complementing region. The normal sequence 5' GTC GTT TTA CAA 3' was changed to GTC GTT T TTA CAA (MIDT) or GTC GTT C TTA CAA (MIDC) to study frameshifts and to GTC GTT CTT TAA (OCHRE) to study reversion of the ochre (TAA) codon. Escherichia coli pol I Kf and T7 DNA polymerase mutant enzymes devoid of 3'-->5' exonuclease activity produced UV-induced revertants at higher frequency than did their exonuclease proficient counterparts. Removal of cyclobutane dimers with photolyase before in vitro synthesis did not greatly affect mutant frequency although such treatment led to significantly increased DNA synthesis by the wild-type T7 DNA polymerase on UV-irradiated substrate. Reversions of the in frame ochre sequence GTT CTT TAA produced by the delta 28 T7 DNA polymerase were mainly by base substitution in the TAA codon. About half of the E. coli Kf exo- enzyme ochre revertants had a TTA deletion. Five mutant T7 DNA polymerases with varying exonuclease activity gave revertant frequencies that correlated better with published values of enzyme velocity than with exonuclease activity or with measured bypass synthesis. Our data indicate that loss of proofreading activity increases the frequency of UV-induced frameshifts, but lack of such activity is not sufficient for their production. We suggest that frameshifts occur more frequently when nucleotide addition opposite the lesion is slow. The same lesion can give rise to a different spectrum of mutations depending on the polymerase.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
240
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
226-42
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Production of UV-induced frameshift mutations in vitro by DNA polymerases deficient in 3'-->5' exonuclease activity.
pubmed:affiliation
Department of Molecular Genetics and Cell Biology, University of Chicago, IL 60637.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.