Wood, E;
(2015)
A study of cell size homeostasis and variability in the fission yeast Schizosaccharomyces pombe.
Doctoral thesis , UCL (University College London).
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Abstract
Proliferating cells maintain a near-constant cell size at division within a given population, suggesting the existence of control mechanisms that buffer cell size perturbations. Wild type cells of the fission yeast Schizosaccharomyces pombe divide within a narrow range of cell sizes around a mean of 14 µm. A proposed model for size sensing in fission yeast involves polar gradients of the kinase Pom1 inhibiting Cdr1/2 at medial cortical nodes until cells surpass a size threshold. This model has been further investigated using size homeostasis analyses on single cells growing in a microfluidic chamber. The results demonstrate that Pom1 is not essential for cells to maintain size homeostasis and as such cannot be the only major player in the size sensing mechanism in fission yeast. This single-cell method has been further exploited to investigate the roles of other known cell cycle regulators in maintaining size homeostasis. The investigation has included cells with a Cdc2-L-Cdc13 fusion protein, which is able to drive the cell cycle in the absence of much of the canonical regulation. In order to elucidate new components responsible for the control of cell size homeostasis, a previous screen of 82% of non-essential genes was used to identify genes which when deleted increase size variability at division. Until now only a few mutations have been described that increase variability in size at division, and these have been shown to directly affect the activity of the cyclin-dependent kinase Cdc2. A follow up of the primary hits from this screen identified 15 genes which when deleted lead to greater variability in size at division. Further size homeostasis analysis on single cells identified two genes that when deleted decrease the ability of cells to sense and/or adequately correct for size deviations.
| Type: | Thesis (Doctoral) |
|---|---|
| Title: | A study of cell size homeostasis and variability in the fission yeast Schizosaccharomyces pombe |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| UCL classification: | UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1473555 |
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