Condensin function in mitotic nucleolar segregation is regulated by rDNA transcription.
Chromosome condensation is established and maintained by the condensin complex. The mechanisms governing loading of condensin onto specific chromosomal sites remain unknown. To elucidate the molecular pathways that determine condensin binding to the nucleolar organizer, a key condensin binding site, we analyzed the properties of condensin-bound sites within the rDNA repeat in budding yeast and demonstrated that the bulk of mitotic condensin binding to rDNA is reduced or eliminated when Pol I transcription is elevated. Conversely, when Pol I transcription is repressed either by rapamycin treatment or by promoter shut-off, condensin binding to rDNA is increased. This novel potential role for constitutive and/or periodic repression of Pol I transcription in rDNA condensin loading is an important factor in determining the segregation proficiency of NOR-containing chromosomes.
Wang
Bi-Dar
BD
NICHD, Laboratory of Gene Regulation and Development, Bethesda, Maryland 20892, USA.
Butylin
Pavel
P
Strunnikov
Alexander
A
D000251:Adenosine Triphosphatases / Q000502:physiology*; D002466:Cell Nucleolus; D020090:Chromosome Segregation; D004275:DNA, Ribosomal / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000502:physiology*; D008938:Mitosis; D046912:Multiprotein Complexes / Q000502:physiology*; D009697:Nucleolus Organizer Region; D012441:Saccharomyces cerevisiae / Q000166:cytology; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology; D014158:Transcription, Genetic
D004275:DNA, Ribosomal; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; C108312:condensin complexes; D000251:Adenosine Triphosphatases