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A new chemical genetics toolbox to analyse genes essential for the mitotic entry

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Version 2 2023-09-27, 08:17
Version 1 2023-06-10, 00:46
thesis
posted on 2023-09-27, 08:17 authored by Adrijana Crncec

Two mitotic cyclins, cyclin A and cyclin B, are believed to promote mitotic events. However, previous studies have implicated both specific requirement and redundancy of these cyclins in human cells in mitosis. Using degron-tagging approaches, the roles of cyclin B were analysed in RPE-1 and in HeLa cells. Striking di_erences were uncovered between the two cell lines. RPE-1 cells require cyclin B for specific substrate phosphorylations only in metaphase, but HeLa cells without cyclin B stall in an intermediate prophase-like stage which was characterized by a specific morphology and a unique pattern of CDK-substrate phosphorylation. In the absence of cyclin B, endogenous levels of cyclin A alone are responsible for establishing this prophase-like stage found in HeLa cells; but overexpressing cyclin A promoted separate mitotic events in a dose-dependent manner. On the other hand, RPE-1 cells rely on a combination of cyclin A-mediated CDK activity, as well as phosphatase inactivation, to promote separate mitotic events. These results implied that HeLa cells depend on the quantity of, rather than the specific, CDKcyclin activity during mitosis, whereas RPE-1 cells require specific CDK phosphorylations conferred by different cyclins. As the expression of mitotic cyclins is altered in many cancer cells, a comprehensive understanding of the regulation of these cyclins in healthy and cancer cells will allow the design of targeted treatments and a better prediction of patient outcome after therapies.

History

File Version

  • Published version

Pages

314

Department affiliated with

  • Sussex Centre for Genome Damage Stability Theses

Qualification level

  • doctoral

Qualification name

  • phd

Language

  • eng

Notes

Dual-degree programme: The Hong Kong University of Science and Technology and University of Sussex

Institution

University of Sussex

Full text available

  • No

Supervisor

Dr. Helfrid Hochegger Prof. Randy Poon

Legacy Posted Date

2021-08-27

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