Genetic and Physical Analysis of Double-Strand Break Repair and Recombination in Saccharomyces Cerevisiae
AUTOR(ES)
Rudin, N.
RESUMO
We have investigated HO endonuclease-induced double-strand break (DSB) recombination and repair in a LACZ duplication plasmid in yeast. A 117-bp MATa fragment, embedded in one copy of LACZ, served as a site for initiation of a DSB when HO endonuclease was expressed. The DSB could be repaired using wild-type sequences located on a second, promoterless, copy of LACZ on the same plasmid. In contrast to normal mating-type switching, crossing-over associated with gene conversion occurred at least 50% of the time. The proportion of conversion events accompanied by exchange was greater when the two copies of LACZ were in direct orientation (80%), than when inverted (50%). In addition, the fraction of plasmids lost was significantly greater in the inverted orientation. The kinetics of appearance of intermediates and final products were also monitored. The repair of the DSB is slow, requiring at least an hour from the detection of the HO-cut fragments to completion of repair. Surprisingly, the appearance of the two reciprocal products of crossing over did not occur with the same kinetics. For example, when the two LACZ sequences were in the direct orientation, the HO-induced formation of a large circular deletion product was not accompanied by the appearance of a small circular reciprocal product. We suggest that these differences may reflect two kinetically separable processes, one involving only one cut end and the other resulting from the concerted participation of both ends of the DSB.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1203726Documentos Relacionados
- A Test of the Double-Strand Break Repair Model for Meiotic Recombination in Saccharomyces Cerevisiae
- Genetic analysis of double-strand break repair in Escherichia coli.
- Genetic Requirements for the Single-Strand Annealing Pathway of Double-Strand Break Repair in Saccharomyces Cerevisiae
- Aberrant Double-Strand Break Repair in rad51 Mutants of Saccharomyces cerevisiae
- Role of Saccharomyces cerevisiae Msh2 and Msh3 repair proteins in double-strand break-induced recombination