Searching across hundreds of databases

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Regulation of nuclear positioning and dynamics of the silent mating type loci by the yeast Ku70/Ku80 complex.

We have examined the hypothesis that the highly selective recombination of an active mating type locus (MAT) with either HMLalpha or HMRa is facilitated by the spatial positioning of relevant sequences within the budding yeast (Saccharomyces cerevisiae) nucleus. However, both position relative to the nuclear envelope (NE) and the subnuclear mobility of fluorescently tagged MAT, HML, or HMR loci are largely identical in haploid a and alpha cells. Irrespective of mating type, the expressed MAT locus is highly mobile within the nuclear lumen, while silent loci move less and are found preferentially near the NE. The perinuclear positions of HMR and HML are strongly compromised in strains lacking the Silent information regulator, Sir4. However, HMLalpha, unlike HMRa and most telomeres, shows increased NE association in a strain lacking yeast Ku70 (yKu70). Intriguingly, we find that the yKu complex is associated with HML and HMR sequences in a mating-type-specific manner. Its abundance decreases at the HMLalpha donor locus and increases transiently at MATa following DSB induction. Our data suggest that mating-type-specific binding of yKu to HMLalpha creates a local chromatin structure competent for recombination, which cooperates with the recombination enhancer to direct donor choice for gene conversion of the MATa locus.

Pubmed ID: 19047366 RIS Download

Mesh terms: Antigens, Nuclear | Cell Nucleus | Chromosomes, Fungal | DNA Breaks, Double-Stranded | DNA Repair | DNA-Binding Proteins | Gene Conversion | Genes, Mating Type, Fungal | Ku Autoantigen | Mutagenesis, Insertional | Mutation | Nuclear Envelope | Operator Regions, Genetic | Protein Binding | Rad52 DNA Repair and Recombination Protein | Recombination, Genetic | Saccharomyces cerevisiae | Saccharomyces cerevisiae Proteins | Telomere