Dissecting the spindle checkpoint response in Cryptococcus neoformans

Background: We study mitosis and chromosome segregation in yeasts, with a particular focus on the spindle checkpoint. This cell cycle control monitors interactions between chromosomes and the mitotic spindle and delays mitotic progression until all pairs of sister chromatids are attached appropriately to spindle microtubules. We employ synthetic biology approaches to analyse this signalling pathway, and have now successfully generated a ‘wait anaphase’ signal entirely independently of kinetochores (1).

Cryptococcus neoformans is an understudied fungal pathogen (2) with a fascinating life cycle. You will focus on the mechanism and quality control of chromosome segregation and how cell cycle reconfiguration helps this yeast adapt to stressful conditions such as those encountered during human infection. During infection Cryptococcus undergoes a striking morphological transition, increasing in size and ploidy to form thick-walled Titan cells. Production of these Titan cells has recently been made possible in vitro (3).

In this project you will employ a combination of synthetic biology, Cryptococcus genetics, biochemical purification, mass spectrometry and live-cell imaging. In particular you will use a combination of live-cell imaging and microfluidics to study Titan cell divisions, chromosome segregation and aneuploidy using fluorescently marked chromosomes and microtubules. You will focus on the roles of the Mps1 spindle checkpoint kinase and introduce SynCheck (1) to Cryptococcus, to study the consequences of prolonged mitotic arrest.

This project provides an excellent training opportunity, due to the breadth of approaches being employed in a genetically tractable yeast that is also an important human pathogen

Lab web site: http://hardwick.bio.ed.ac.uk/