Four chromo-domain proteins of Schizosaccharomyces pombe differentially repress transcription at various chromosomal locations.
Transcription is repressed in regions of the fission yeast genome close to centromeres, telomeres, or the silent mating-type cassettes mat2-P and mat3-M. The repression involves the chromo-domain proteins Swi6 and Clr4. We report that two other chromo-domain proteins, Chp1 and Chp2, are also important for these position effects. Chp1 showed a specificity for centromeric regions. Its essentiality for the transcriptional repression of centromeric markers correlates with its importance for chromosome stability. Chp2 appeared more pleiotropic. Its effects on centromeric silencing were less pronounced than those of Chp1, and it participated in telomeric position effects and transcriptional silencing in the mating-type region. We also found that PolII-transcribed genes were repressed when placed in one of the Schizosaccharomyces pombe rDNA clusters, a situation analogous to that in the budding yeast Saccharomyces cerevisiae. Chp2, Swi6, Clr4, and, to a lesser extent, Chp1 participated in that repression.
Thon
G
G
Department of Genetics, Institute of Molecular Biology, University of Copenhagen, Denmark. gen@biobase.dk
Verhein-Hansen
J
J
D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides; D030161:Avian Proteins; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D015825:Chromosomes, Fungal; D004258:DNA Polymerase III / Q000235:genetics; D017931:DNA Primers; D004275:DNA, Ribosomal / Q000235:genetics; D023082:Defensins; D017353:Gene Deletion; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D012091:Repetitive Sequences, Nucleic Acid; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D016615:Telomere; D014158:Transcription, Genetic / Q000502:physiology*
D023181:Antimicrobial Cationic Peptides; D030161:Avian Proteins; D018797:Cell Cycle Proteins; C115018:Chp1 protein, S pombe; D017931:DNA Primers; D004275:DNA, Ribosomal; D023082:Defensins; D010455:Peptides; D029702:Schizosaccharomyces pombe Proteins; C086738:gallinacin 2 protein, chicken; D004258:DNA Polymerase III