Yeast Mating, cell fusion and lysis

PABLO AGUILAR; AGUSTINA OLIVERA-COUTO; PETER WALTER; FEDERICO ZANCHETTA

Conferencia; Membranes in Motion (A5); 2012

Keystone Symposia

Fusion between cells underlies developmental events from fertilization to the genesis ofsyncytial tissues. Cell-cell fusion has also been implicated in regeneration of tissues afterinjury, and in initiation and progression of cancer. The ultimate molecular machineriesthat catalyze cell-cell fusion are recently being characterized in nematodes but in othermodel systems they are still missing. We use yeast mating mating as a model touncover them. During mating, Saccharomyces cerevisiae haploid cells of oppositemating types differentiate into competent gametes to merge in a diploid cell. Using thismodel we have found that the plasma membrane protein Prm1 and extracellular calciumplay a key role at the cell-cell fusion step. Our working model proposes that both Prm1and extracellular calcium regulate the fidelity of the cell-cell fusion reaction: in theirabsence cell-cell fusion turns into cell lysis. Thus, cell lysis is an ?undesirable? byproductof the cell fusion machinery that we will exploit to perform genetic screens. Usingbiochemical and robotic methods we execute genomic screens aimed to identify genesthat mediate cell lysis during mating. Preliminary results validate this approachuncovering genes involved in pheromone-induced calcium uptake as lysis enhancers.(This work is supported by ICGEB-CRP_URU11_01).