Nucleolar segregation lags behind the rest of the genome and requires Cdc14p activation by the FEAR network.
In order to transmit a full genetic complement cells must ensure that all chromosomes are accurately split and distributed during anaphase. Chromosome XII in S. cerevisiae contains the site of nucleolar assembly, a 1-2Mb array of rDNA genes named RDN1. Cdc14p is a conserved phosphatase, essential for anaphase progression and mitotic exit, which is kept inactive at the nucleolus until mitosis. In early anaphase, the FEAR network (Cdc Fourteen Early Anaphase Release) promotes the transient and partial release of Cdc14p from the nucleolus. The putative role of Cdc14p released by the FEAR network is thought to be the stimulation of full Cdc14p release by activation of the GTPase-driven signaling cascade (the Mitotic Exit Network or MEN) that ensures mitotic exit. Here, we show that nucleolar segregation is spatially separated and temporally delayed from the rest of the genome. Nucleolar segregation occurs during mid-anaphase and coincides with the FEAR release of Cdc14p. Inactivation of FEAR delays nucleolar segregation until late anaphase, demonstrating that one function of the FEAR network is to promote segregation of repetitive nucleolar chromatin during mid-anaphase.
Cell Cycle Group, Clinical Sciences Center, Medical Research Council, Imperial College London, London, UK.
Jordi
J
Torres-Rosell
Félix
F
Machín
Adam
A
Jarmuz
Luis
L
Aragón
D000705:Anaphase; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism; D002466:Cell Nucleolus / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002469:Cell Separation; D002843:Chromatin / Q000378:metabolism; D004275:DNA, Ribosomal / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000378:metabolism; D017353:Gene Deletion; D005786:Gene Expression Regulation; D016678:Genome; D016681:Genome, Fungal; D005838:Genotype; D006801:Humans; D008856:Microscopy, Fluorescence; D008938:Mitosis; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors
C074860:CDC14 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D004275:DNA, Ribosomal; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases