Genetic Engineering of S. cerevisiae Lab 

The HHMI lab conducted during the first semester revolves around the genetic modification of Saccharomyces cerevisiae (baker's yeast). The overall objective is to remove the function of one particular gene and observe the effect on growth rate. Our gene of choice was the TOS3 gene, which plays a role in responding to nutrient stress and in the activation of SNF1 kinase (regulates cell cycle and required for yeast to grow on certain substances). There are three genes (one being TOS3) in the genome of S. cerevisiae that activate SNF1, but TOS3 is known to have the greatest impact on SNF1 when the yeast is grown on a non-fermentable carbon source, such as ethanol. A non-fermentable carbon source forces the yeast to grow aerobically (yeast grow aerobically and anaerobically). The most effective non-fermentable carbon source is potassium acetate.