Brc1-mediated rescue of Smc5/6 deficiency: requirement for multiple nucleases and a novel Rad18 function

Lee, K.M., Nizza, S, Hayes, T, Bass, K.L., Irmisch, A, Murray, J.M. and O'Connell, M.J. (2007) Brc1-mediated rescue of Smc5/6 deficiency: requirement for multiple nucleases and a novel Rad18 function. Genetics, 175. pp. 1585-1595. ISSN 0016-6731

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Abstract

Smc5/6 is a structural maintenance of chromosomes complex, related to the cohesin and condensin complexes. Recent studies implicate Smc5/6 as being essential for homologous recombination. Each gene is essential, but hypomorphic alleles are defective in the repair of a diverse array of lesions. A particular allele of smc6 (smc6-74) is suppressed by overexpression of Brc1, a six-BRCT domain protein that is required for DNA repair during S-phase. This suppression requires the postreplication repair (PRR) protein Rhp18 and the structure-specific endonucleases Slx1/4 and Mus81/Eme1. However, we show here that the contribution of Rhp18 is via a novel pathway that is independent of PCNA ubiquitination and PRR. Moreover, we identify Exo1 as an additional nuclease required for Brc1-mediated suppression of smc6-74, independent of mismatch repair. Further, the Apn2 endonuclease is required for the viability of smc6 mutants without extrinsic DNA damage, although this is not due to a defect in base excision repair. Several nucleotide excision repair genes are similarly shown to ensure viability of smc6 mutants. The requirement for excision factors for the viability of smc6 mutants is consistent with an inability to respond to spontaneous lesions by Smc5/6-dependent recombination.

Item Type: Article
Keywords: Base Sequence Cell Cycle Proteins/*genetics/*metabolism Chromosomal Proteins, Non-Histone/*genetics/*metabolism DNA Repair/genetics DNA, Fungal/genetics DNA-(Apurinic or Apyrimidinic Site) Lyase/genetics/metabolism Exodeoxyribonucleases/genetics/metabolism Genes, Fungal Mutation Recombination, Genetic Schizosaccharomyces/*genetics/growth & development/*metabolism Schizosaccharomyces pombe Proteins/*genetics/*metabolism
Schools and Departments: School of Life Sciences
Depositing User: Gee Wheatley
Date Deposited: 29 Jul 2008
Last Modified: 13 Mar 2017 12:02
URI: http://sro.sussex.ac.uk/id/eprint/1808
Google Scholar:13 Citations

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