A common truncation is toxic to cells entering quiescence and promotes sporulation.

Ssd1p is an RNA binding protein in that plays an important role in cell division, cell fate decisions, stress response and virulence. Lab strain W303 encodes the terminal truncation which is typically interpreted to be a loss of function allele. We have shown that is toxic to mutants and to diploids entering stationary phase and quiescence. The null shows no toxicity, indicating that is disrupting an essential function that does not solely require Ssd1p. cells are also more sensitive to stress than . These phenotypes are recessive to . In contrast, plays a dominant role in promoting sporulation.