An Introduction to CRISPR-Mediated Genome Editing in Fungi

Central dogma, transformation, and genome editing are key biological concepts for which junior scientists must gain experience during training. Here we present an exercise that introduces these concepts in a single practical laboratory exercise. Our exercise utilizes CRISPR/Cas9 genome editing to introduce a stop codon into Saccharomyces cerevisiae ADE2. This edit leads to the buildup of an adenine precursor that dyes the edited cells red. As the repair template, guide RNA, and Cas9 are all encoded in our vector, transformation can be performed in 2 hours. Furthermore, since all components of the Cas9/CRISPR system are encoded by the vector, specialized equipment and reagents, such as a PCR machine or oligonucleotides, are not required to perform the experiments as designed. As such, these exercises provide an efficient cost-effective introduction to a wide variety of key molecular biology concepts and lay the foundation for more rigorous investigations in upper-level classes and independent research projects.