Linked Life Data

8737989

Source:http://linkedlifedata.com/resource/pubmed/id/8737989

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1997-1-21
pubmed:abstractText
We have developed a versatile plasmid vector (pReco-sigma) for recombination studies. When linearized and introduced into the cells of interest, pReco-sigma allows the simultaneous determination of the relative frequencies of homologous recombination versus nonhomologous DNA-end joining (also termed end-to-end joining), the latter an example of illegitimate recombination processes. As a system we made use of stage VI oocytes and fertilized eggs of the African clawed frog Xenopus laevis, which were previously described to support homologous recombination and DNA-end joining, respectively. Extending these earlier findings, we show that oocytes yield > 80% of the homologously recombined product, whereas in eggs a highly efficient DNA-end joining activity predominates (> 95%). Both reactions, homologous recombination and DNA-end joining, are shown to occur quickly, with the majority of the respective products being formed within the first 20 minutes of incubation under optimal conditions. In fertilized eggs, up to 50% of all injected linear DNA molecules are recircularized by DNA-end joining. With high amounts of injected DNA per fertilized egg, DNA-end joining is reduced, presumably due to competition for essential factors, and homologous recombination becomes readily detectable. As there is a sequence of rapid cleavage divisions after fertilization of the egg, the fast and highly efficient DNA-end joining, even though it is error-prone at the junction site, seems to be best suited to cope with DNA double-strand breaks that might occur in the genome during early embryogenesis. On the other hand, the long-lived oocytes seem to repair DNA double-strand breaks via homologous recombination. This latter property may be exploited both in Xenopus and in other organisms to achieve homologous integration of exogenous DNA into germ cells for gene targeting.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0177-3593
pubmed:author
pubmed:issnType
Print
pubmed:volume
377
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
239-50
pubmed:dateRevised
2006-5-1
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Dramatic changes in the ratio of homologous recombination to nonhomologous DNA-end joining in oocytes and early embryos of Xenopus laevis.
pubmed:affiliation
Institut für Molekularbiologie II, Universität Zürich, Switzerland.
pubmed:publicationType
Journal Article