The tight linkage between DNA replication and double-strand break repair in bacteriophage T4
AUTOR(ES)
George, James W.
FONTE
The National Academy of Sciences
RESUMO
Double-strand break (DSB) repair and DNA replication are tightly linked in the life cycle of bacteriophage T4. Indeed, the major mode of phage DNA replication depends on recombination proteins and can be stimulated by DSBs. DSB-stimulated DNA replication is dramatically demonstrated when T4 infects cells carrying two plasmids that share homology. A DSB on one plasmid triggered extensive replication of the second plasmid, providing a useful model for T4 recombination-dependent replication (RDR). This system also provides a view of DSB repair in T4-infected cells and revealed that the DSB repair products had been replicated in their entirety by the T4 replication machinery. We analyzed the detailed structure of these products, which do not fit the simple predictions of any of three models for DSB repair. We also present evidence that the T4 RDR system functions to restart stalled or inactivated replication forks. First, we review experiments involving antitumor drug-stabilized topoisomerase cleavage complexes. The results suggest that forks blocked at cleavage complexes are resolved by recombinational repair, likely involving RDR. Second, we show here that the presence of a T4 replication origin on one plasmid substantially stimulated recombination events between it and a homologous second plasmid that did not contain a T4 origin. Furthermore, replication of the second plasmid was increased when the first plasmid contained the T4 origin. Our interpretation is that origin-initiated forks become inactivated at some frequency during replication of the first plasmid and are then restarted via RDR on the second plasmid.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=37434Documentos Relacionados
- Repair of Double-Strand Breaks in Bacteriophage T4 by a Mechanism That Involves Extensive DNA Replication
- Recombination-dependent DNA replication stimulated by double-strand breaks in bacteriophage T4.
- SMC1 coordinates DNA double-strand break repair pathways
- Evidence for the double-strand break repair model of bacteriophage lambda recombination.
- Double-strand break repair in Ku86- and XRCC4-deficient cells.