asymmetry; yeast; modelling; image analysis; spindle poles; septation initiation network; cell cycle; cytokinesis; mitosis; S.pombe
Chasapi Anastasia, Wachowicz Paulina, Niknejad Anne, Collin Philippe, Krapp Andrea, Cano Elena, Simanis Viesturs, Xenarios Ioannis (2015), An Extended, Boolean Model of the Septation Initiation Network in S.Pombe Provides Insights into Its Regulation., in PloS one
, 10(8), 0134214-0134214.
Wachowicz Paulina, Chasapi Anastasia, Krapp Andrea, Cano Del Rosario Elena, Schmitter Daniel, Sage Daniel, Unser Michael, Xenarios Ioannis, Rougemont Jacques, Simanis Viesturs (2015), Analysis of S. pombe SIN protein association to the SPB reveals two genetically separable states of the SIN., in Journal of cell science
, 128(4), 741-54.
Schmitter Daniel, Wachowicz Paulina, Sage Daniel, Chasapi Anastasia, Xenarios Ioannis, Simanis Viesturs, Unser Michael (2013), A 2D/3D image analysis system to track fluorescently labeled structures in rod-shaped cells: application to measure spindle pole asymmetry during mitosis., in Cell division
, 8(1), 6-6.
Asymmetric events within a cell are of fundamental importance in biology. In multicellular organisms, they determine cell fate during development, and are essential for maintaining stem cells in the adult organism; asymmetry of centrosome behaviour and inheritance is also being implicated in an increasing number of cellular and developmental processes. Asymmetry is also important in unicellular organisms; for example, differences in mRNA segregation between cells, or imprinting of individual DNA strands, determine the pattern of mating type switching. The yeast spindle pole body (SPB) is the functional counterpart of the centrosome in mammalian cells. In addition to its role as a microtubule organising center, it also serves as a coordination point for signalling molecules that govern cell cycle progression.The fission yeast SIN, which controls the initiation of cytokinesis, represents a relatively simple protein kinase signalling network that is associated with the SPB. Though it may have cytoplasmic roles, all its functions require SPB-associated scaffold proteins. In wild-type cells, the signalling proteins are distributed asymmetrically, associating with the new SPB in anaphase. This active, asymmetric, late-mitotic configuration of the SIN on the SPBs is generated from an early mitotic, visually symmetrical state. Understanding the rules that govern this in a wild-type cell, and how this asymmetry is perturbed in mutant cells, or in response to physiological changes in the environment may provide important insights into how SPB asymmetry is generated in this organism. As with other studies of complex processes that have been performed in model systems, for example regulation of the cell cycle, the expectation is that the insights provided by relatively simple organisms will provide important pointers for how asymmetry of centrosome function is generated in complex organisms. The goal of the research proposed here is to understand the “rules” that govern when SIN proteins, and by implication SPBs, become asymmetric during anaphase B. This study will be undertaken as a collaboration between the laboratories of Professor M. Unser (EPFL), who will develop the tracking and analysis programs to enable analysis of the images, the group of Dr. Ioannis Xenarios (Swiss Institute for Bioinformatics, Vital-IT center), who will develop a qualitative model of the behaviour of the SIN and Professor Viesturs Simanis, who will undertake the “wet-lab” analysis of fission yeast.