AI Article Synopsis
- A chromosome fragmentation assay in Saccharomyces cerevisiae revealed high efficiency of break-induced replication (BIR) involving telomere generation and recombination over 100 kb of chromosomal sequences.
- RAD51 plays a crucial role in over 95% of BIR events and is essential for creating chromosome fragments through single-end and two-event processes.
- The study found that RAD52 is essential for BIR at unique sequences, while mutations in RAD50 or RAD59 did not significantly affect BIR efficacy in both RAD51 and rad51 strains.
Article Abstract
A chromosome fragmentation assay was used to measure the efficiency and genetic control of break-induced replication (BIR) in Saccharomyces cerevisiae. Formation of a chromosome fragment by de novo telomere generation at one end of the linear vector and recombination-dependent replication of 100 kb of chromosomal sequences at the other end of the vector occurred at high frequency in wild-type strains. RAD51 was required for more than 95% of BIR events involving a single-end invasion and was essential when two BIR events were required for generation of a chromosome fragment. The similar genetic requirements for BIR and gene conversion suggest a common strand invasion intermediate in these two recombinational repair processes. Mutation of RAD50 or RAD59 conferred no significant defect in BIR in either RAD51 or rad51 strains. RAD52 was shown to be essential for BIR at unique chromosomal sequences, although rare recombination events were detected between the subtelomeric Y' repeats.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC355873 | PMC |
| http://dx.doi.org/10.1128/MCB.24.6.2344-2351.2004 | DOI Listing |
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Article Synopsis
- Replication forks encountering unrepaired single-strand breaks (SSBs) can lead to both single-ended (seDSBs) and double-ended double-strand breaks (deDSBs), which are significant in cancer development.
- The study reveals that in fission yeast, SSBs typically result in deDSBs repaired by homologous recombination, but can also initiate break-induced replication (BIR).
- The occurrence of BIR is more frequent when DNA replication fork convergence is delayed and the Ku70 protein, involved in non-homologous end joining, is absent.
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