title: Expression of cancer related BRCA1 missense variants decreases MMS-induced recombination in Saccharomyces cerevisiae without altering its nuclear localization.
abstract: BRCA1 tumor suppressor gene is found mutated in familial breast and ovarian cancer. Most cancer related mutations were found located at the RING (Really Interesting New Gene) and at the BRCT (BRca1 C-Terminal) domain. However, 20 y after its identification, the biological role of BRCA1 and which domains are more relevant for tumor suppression are still being elucidated. We previously reported that expression of BRCA1 cancer related variants in the RING and BRCT domain increases spontaneous homologous recombination in yeast indicating that BRCA1 may interact with yeast DNA repair/recombination. To finally demonstrate whether BRCA1 interacts with yeast DNA repair, we exposed yeast cells expressing BRCA1wt, the cancer-related variants C-61G and M1775R to different doses of the alkylating agent methyl methane-sulfonate (MMS) and then evaluated the effect on survival and homologous recombination. Cells expressing BRCA1 cancer variants were more sensitive to MMS and less inducible to recombination as compared to cell expressing BRCA1wt. Moreover, BRCA1-C61G and -M1775R did not change their nuclear localization form as compared to the BRCA1wt or the neutral variant R1751Q indicating a difference in the DNA damage processing. We propose a model where BRCA1 cancer variants interact with the DNA double strand break repair pathways producing DNA recombination intermediates, that maybe less repairable and decrease MMS-induced recombination and survival. Again, this study strengthens the use of yeast as model system to characterize the mechanisms leading to cancer in humans carrying the BRCA1 missense variant.
authors.affiliation: a Yeast Genetics and Genomics, Institute of Clinical Physiology , CNR, Pisa , Italy.
authors.forename: Samuele
authors.initials: S
authors.lastname: Lodovichi
authors.affiliation: a Yeast Genetics and Genomics, Institute of Clinical Physiology , CNR, Pisa , Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Vitello
authors.affiliation: a Yeast Genetics and Genomics, Institute of Clinical Physiology , CNR, Pisa , Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Cervelli
authors.affiliation: a Yeast Genetics and Genomics, Institute of Clinical Physiology , CNR, Pisa , Italy.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Galli
mesh_terms: D019313:BRCA1 Protein / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D059765:Homologous Recombination / Q000235:genetics*; D006801:Humans; D008741:Methyl Methanesulfonate / Q000494:pharmacology*; D050505:Mutant Proteins / Q000378:metabolism; D020125:Mutation, Missense / Q000235:genetics*; D021381:Protein Transport / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics*
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D050505:Mutant Proteins; D008741:Methyl Methanesulfonate
keywords: BRCA1; Methyl methanesulfonate; Saccharomyces cerevisiae; homologous recombination; nuclear localization