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Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition.
PLoS Genet. 2020 02; 16(2):e1008608.PG

Abstract

DNA double-strand breaks (DSBs) are toxic forms of DNA damage that must be repaired to maintain genome integrity. Telomerase can act upon a DSB to create a de novo telomere, a process that interferes with normal repair and creates terminal deletions. We previously identified sequences in Saccharomyces cerevisiae (SiRTAs; Sites of Repair-associated Telomere Addition) that undergo unusually high frequencies of de novo telomere addition, even when the original chromosome break is several kilobases distal to the eventual site of telomerase action. Association of the single-stranded telomere binding protein Cdc13 with a SiRTA is required to stimulate de novo telomere addition. Because extensive resection must occur prior to Cdc13 binding, we utilized these sites to monitor the effect of proteins involved in homologous recombination. We find that telomere addition is significantly reduced in the absence of the Rad51 recombinase, while loss of Rad52, required for Rad51 nucleoprotein filament formation, has no effect. Deletion of RAD52 suppresses the defect of the rad51Δ strain, suggesting that Rad52 inhibits de novo telomere addition in the absence of Rad51. The ability of Rad51 to counteract this effect of Rad52 does not require DNA binding by Rad51, but does require interaction between the two proteins, while the inhibitory effect of Rad52 depends on its interaction with Replication Protein A (RPA). Intriguingly, the genetic interactions we report between RAD51 and RAD52 are similar to those previously observed in the context of checkpoint adaptation. Forced recruitment of Cdc13 fully restores telomere addition in the absence of Rad51, suggesting that Rad52, through its interaction with RPA-coated single-stranded DNA, inhibits the ability of Cdc13 to bind and stimulate telomere addition. Loss of the Rad51-Rad52 interaction also stimulates a subset of Rad52-dependent microhomology-mediated repair (MHMR) events, consistent with the known ability of Rad51 to prevent single-strand annealing.

Authors+Show Affiliations

Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

32012161

Citation

Epum, Esther A., et al. "Interaction of Yeast Rad51 and Rad52 Relieves Rad52-mediated Inhibition of De Novo Telomere Addition." PLoS Genetics, vol. 16, no. 2, 2020, pp. e1008608.
Epum EA, Mohan MJ, Ruppe NP, et al. Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition. PLoS Genet. 2020;16(2):e1008608.
Epum, E. A., Mohan, M. J., Ruppe, N. P., & Friedman, K. L. (2020). Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition. PLoS Genetics, 16(2), e1008608. https://doi.org/10.1371/journal.pgen.1008608
Epum EA, et al. Interaction of Yeast Rad51 and Rad52 Relieves Rad52-mediated Inhibition of De Novo Telomere Addition. PLoS Genet. 2020;16(2):e1008608. PubMed PMID: 32012161.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition. AU - Epum,Esther A, AU - Mohan,Michael J, AU - Ruppe,Nicholas P, AU - Friedman,Katherine L, Y1 - 2020/02/03/ PY - 2019/08/06/received PY - 2020/01/13/accepted PY - 2020/02/13/revised PY - 2020/2/6/pubmed PY - 2020/5/12/medline PY - 2020/2/4/entrez SP - e1008608 EP - e1008608 JF - PLoS genetics JO - PLoS Genet VL - 16 IS - 2 N2 - DNA double-strand breaks (DSBs) are toxic forms of DNA damage that must be repaired to maintain genome integrity. Telomerase can act upon a DSB to create a de novo telomere, a process that interferes with normal repair and creates terminal deletions. We previously identified sequences in Saccharomyces cerevisiae (SiRTAs; Sites of Repair-associated Telomere Addition) that undergo unusually high frequencies of de novo telomere addition, even when the original chromosome break is several kilobases distal to the eventual site of telomerase action. Association of the single-stranded telomere binding protein Cdc13 with a SiRTA is required to stimulate de novo telomere addition. Because extensive resection must occur prior to Cdc13 binding, we utilized these sites to monitor the effect of proteins involved in homologous recombination. We find that telomere addition is significantly reduced in the absence of the Rad51 recombinase, while loss of Rad52, required for Rad51 nucleoprotein filament formation, has no effect. Deletion of RAD52 suppresses the defect of the rad51Δ strain, suggesting that Rad52 inhibits de novo telomere addition in the absence of Rad51. The ability of Rad51 to counteract this effect of Rad52 does not require DNA binding by Rad51, but does require interaction between the two proteins, while the inhibitory effect of Rad52 depends on its interaction with Replication Protein A (RPA). Intriguingly, the genetic interactions we report between RAD51 and RAD52 are similar to those previously observed in the context of checkpoint adaptation. Forced recruitment of Cdc13 fully restores telomere addition in the absence of Rad51, suggesting that Rad52, through its interaction with RPA-coated single-stranded DNA, inhibits the ability of Cdc13 to bind and stimulate telomere addition. Loss of the Rad51-Rad52 interaction also stimulates a subset of Rad52-dependent microhomology-mediated repair (MHMR) events, consistent with the known ability of Rad51 to prevent single-strand annealing. SN - 1553-7404 UR - https://www.unboundmedicine.com/medline/citation/32012161/Interaction_of_yeast_Rad51_and_Rad52_relieves_Rad52_mediated_inhibition_of_de_novo_telomere_addition_ L2 - https://dx.plos.org/10.1371/journal.pgen.1008608 DB - PRIME DP - Unbound Medicine ER -