RNase-sensitive DNA modification(s) initiates S. pombe mating-type switching

RNase-sensitive DNA modification(s) initiates S. pombe mating-type switching.

Mating-type switching in fission yeast depends on an imprint at the mat1 locus. Previous data showed that the imprint is made in the DNA strand replicated as lagging. We now identify this imprint as an RNase-sensitive modification and suggest that it consists of one or two RNA residues incorporated into the mat1 DNA. Formation of the imprint requires swi1- and swi3-dependent pausing of the repl...

Remarkably high rate of DNA amplification promoted by the mating-type switching mechanism in Schizosaccharomyces pombe.

A novel mating-type switching-defective mutant showed a highly unstable rearrangement at the mating-type locus (mat1) in fission yeast. The mutation resulted from local amplification of a 134-bp DNA fragment by the mat1-switching phenomenon. We speculate that the rolling-circle-like replication and homologous recombination might be the general mechanisms for local genome region expansion.

Mating-type Mutations in Schzzosaccharomyces Pombe:

Mutants defective in various steps of the sexual cycle have been isolated from homothallic strains of Schizosaccharomyces pombe by BRESCH, MULLER and EGEL (1968). These mutants include heterothallic h+ and hstrains. We have isolated additional h+ and hmutants from homothallic strains. Those mutants which are due to mutations in the mating-type region were analyzed in detail. Our results show th...

Mating-type gene switching in Saccharomyces cerevisiae.

The study of yeast mating-type (MAT) gene switching has provided insights into several aspects of the regulation of gene expression. MAT switching is accomplished by a highly programmed site-specific homologous recombination event in which mating-type-specific sequences at MAT are replaced by alternative DNA sequences copied from one of two unexpressed donors. The mating-type system has also pr...

Histone modifications after DNA damage affect survival in Schizosaccharomyces pombe