The C′ AID-GFP library can be applied to the study of protein essentiality. (A) Schematics representing our pipeline to test protein essentiality in different media. The arrayed yeast collection can be grown in different types of solid media with and without induction of the AID system. The ratio of the colony size, or relative growth, is indicative of whether the protein depleted is important for growth rate or viability. (B) Heatmap showing the relative growth of every strain in the collection in three different media. The vast majority of the strains (89%) display no severe growth defect upon induction of degradation, except for 601 strains. The results are very similar for all the media tested, with specific strains displaying altered growth in one or more media. Strains were grown in duplicates and for two consecutive plate replications. (C) Venn diagram summarizing the results from panel B for all the strains with a growth defect bigger than 50%. Most of these strains (347) displayed a severe growth defect in every media. The top three GO slim terms for biological processes associated with each group of strains are displayed, together with the percentage of the GO slim term covered in the group. A clear relationship between the media analyzed and the processes affected can be appreciated. (D) Growth curves of a selected example for a protein that is essential, as Npl4, or cause a fitness loss, as Mon2, upon depletion (orange series). Both our system and a GAL1-promotor swap reproduce the results seen in panel B. The average of three repeats with their standard deviation is shown.