Lte1, Cdc14 and MEN-controlled Cdk inactivation in yeast coordinate rDNA decompaction with late telophase progression.
The mechanism of chromatin compaction in mitosis has been well studied, while little is known about what controls chromatin decompaction in early G1 phase. We have localized the Condensin subunit Brn1 to a compact spiral of rDNA in mitotic budding yeast cells. Brn1 release and the resulting rDNA decompaction in late telophase coincided with mitotic spindle dissociation, and occurred asymmetrically (daughter cells first). We immunoprecipitated the GTP-exchange factor Lte1, which helps activate the mitotic exit network (MEN) in anaphase, with mitotic Brn1. In lteDelta cells Brn1 release was delayed, even at temperatures that do not impair mitotic exit. Mutations in MEN pathway components that act downstream of Lte1 similarly delayed rDNA decompaction. We found that Brn1 release in wild-type cells coincided with the release of Cdc14 phosphatase from the nucleolus and with mitotic CDK inactivation, yet it could be selectively delayed by perturbation of the MEN pathway. This may argue that different levels of Cdk inactivation control spindle disassembly and chromatin decompaction. Mutation of lte1 also impaired rotation of the nucleus in early G1.
Varela
Elisa
E
Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
Shimada
Kenji
K
Laroche
Thierry
T
Leroy
Didier
D
Gasser
Susan M
SM
D000251:Adenosine Triphosphatases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004271:DNA, Fungal / Q000378:metabolism*; D004275:DNA, Ribosomal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D017353:Gene Deletion; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D046912:Multiprotein Complexes / Q000378:metabolism; D011485:Protein Binding; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013692:Telophase
C074860:CDC14 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; C089357:LTE1 protein, S cerevisiae; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; C108312:condensin complexes; D018844:Cyclin-Dependent Kinases; D017027:Protein Tyrosine Phosphatases; D000251:Adenosine Triphosphatases