Mitosis and thermosensitive mutants in yeast

**An exemple using fast temperature controller for S. pombe dynamic cell cycle control**

During S. pombe division, the CDC25 protein is required for mitosis completion. At 25°C the CDC25 protein is functional (Fig. 1a) but over 37°C it becomes non-functional or inactivated (Fig. 1b). Such a mutant is called “thermosensitive” and as mitosis only occurs at 25°C, this temperature is termed “permissive”. In these experiments, we used the ElveflowTemp precise temperature control, yet before impossible to achieve, to impact S. pombe physiology during cell division.

ElveflowTemp induced cell cycle phenotype

CDC25 ts S. pombe reversible control of mitosis arrest by CherryTemp copy — Fig 2: CDC25 ts S. pombe reversible control of mitosis arrest by ElveflowTemp Yeast division occurs normally at 25°C (a) but is suddenly stopped when temperature is quickly shifted to 37°C (b). Mitosis only restarts when temperature is set back to 25°C (c, d, e, f)

During our experimentation, S. pombe thermosensitive mutants (CDC25 ts) were examined under the microscope with a ElveflowTemp platform. This system allowed to selectively modify the temperature of yeast samples between 25°C and 37°C resulting in a reversible arrest of mitosis.

This application note refers to:

G. Velve Casquillas, C. Fu, M Le Berre, J. Cramer, S. Meance, A. Plecis, D. Baigl, JJ. Greffet, Y. Chen, M. Piel and PT. Tran Fast microfluidic temperature control for high resolution live cell imaging, Lab on a chip 2010