Intrinsic and cyclin-dependent kinase-dependent control of spindle pole body duplication in budding yeast.
Centrosome duplication must be tightly controlled so that duplication occurs only once each cell cycle. Accumulation of multiple centrosomes can result in the assembly of a multipolar spindle and lead to chromosome mis-segregation and genomic instability. In metazoans, a centrosome-intrinsic mechanism prevents reduplication until centriole disengagement. Mitotic cyclin/cyclin-dependent kinases (CDKs) prevent reduplication of the budding yeast centrosome, called a spindle pole body (SPB), in late S-phase and G2/M, but the mechanism remains unclear. How SPB reduplication is prevented early in the cell cycle is also not understood. Here we show that, similar to metazoans, an SPB-intrinsic mechanism prevents reduplication early in the cell cycle. We also show that mitotic cyclins can inhibit SPB duplication when expressed before satellite assembly in early G1, but not later in G1, after the satellite had assembled. Moreover, electron microscopy revealed that SPBs do not assemble a satellite in cells expressing Clb2 in early G1. Finally, we demonstrate that Clb2 must localize to the cytoplasm in order to inhibit SPB duplication, suggesting the possibility for direct CDK inhibition of satellite components. These two mechanisms, intrinsic and extrinsic control by CDK, evoke two-step system that prevents SPB reduplication throughout the cell cycle.
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Related Subject Headings
- Spindle Apparatus
- Saccharomycetales
- Saccharomyces cerevisiae Proteins
- Plasmids
- Models, Biological
- Mitosis
- Microscopy, Electron
- Genome
- Gene Expression Regulation, Fungal
- Developmental Biology
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Spindle Apparatus
- Saccharomycetales
- Saccharomyces cerevisiae Proteins
- Plasmids
- Models, Biological
- Mitosis
- Microscopy, Electron
- Genome
- Gene Expression Regulation, Fungal
- Developmental Biology