Linked Life Data

9609718

Source:http://linkedlifedata.com/resource/pubmed/id/9609718

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
1998-6-22
pubmed:abstractText
The key step in skin cancer induction by UV light is thought to be the mutagenic DNA synthesis past a DNA photoproduct in a proto-oncogene or tumor suppressor gene. To investigate this critical step, we have constructed an SV40 vector containing a cis-syn thymine dimer, the major DNA photoproduct induced by UVB light, within an AseI site at a location that would initially be replicated by leading strand synthesis. When the dimer-containing SV40 vector was incubated with cell-free HeLa extracts in the presence of TAg, and then digested with AseI, a 2325 bp fragment corresponding to inhibition of cleavage at the dimer site was observed, suggesting that the dimer had terminated synthesis and/or had been bypassed. When the reaction was limited to one round of replication and the products of restriction enzyme digestion were examined by denaturing gel electrophoresis, bands corresponding to both termination and bypass were observed in roughly a one-to-one ratio. Whereas increasing the dNTP concentration from 10 microM to 1 mM increased the ratio of bypass to termination from 0.6 to 2.6, it had no effect on the site of termination, which occurred exclusively one nucleotide before the dimer. Experiments in which dGTP was held constant at 25 microM and various combinations of the remaining nucleotides were raised from 25 microM to 1 mM showed substantial increases in the bypass-to-termination ratio, with the greatest effect seen for raising all three nucleotides to 1 mM. Replication by primary fibroblast XPV extracts was also investigated and found to be greatly stimulated by rhRPA, whereas the stimulatory effect for HeLa cell extracts was variable. In the presence of rhRPA, the XPV extracts were also found to bypass the cis-syn dimer, which contrasts with a recent report that could not detect dimer bypass in SV40 transformed XPV extracts in the absence of added replication factors [Cordeiro-Stone, M., et al. (1997) J. Biol. Chem. 272, 13945-13954].
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8218-26
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Bypass of a site-specific cis-Syn thymine dimer in an SV40 vector during in vitro replication by HeLa and XPV cell-free extracts.
pubmed:affiliation
Department of Chemistry, Washington University, St. Louis, Missouri 63110, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.