Using CRISPR/Cas9 for Large Fragment Deletions in Saccharomyces cerevisiae.

CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9) systems have emerged as a powerful tool for genome editing in many organisms. The wide use of CRISPR/Cas9 systems may be due to the fact that these systems contain a simple guide RNA (sgRNA) that is relatively easy to design and they are very versatile with the ability to simultaneously target multiple genes within a cell ( Varshney et al., 2015 ). We have developed a CRISPR/Cas9 system to delete large genomic fragments (exceeding 30 kb) in Saccharomyces cerevisiae. One application of this technology is to study the effects of large-scale deletions of non-essential genes which may give insight into the function of gene clusters within chromosomes at the molecular level. In this protocol, we describe the general procedures for large fragment deletion in S. cerevisiae using CRISPR/Cas9 including: how to design CRISPR arrays and how to construct Cas9-crRNA expression plasmids as well as how to detect mutations introduced by the system within S. cerevisiae cells.