Conversion Tract Analysis of Homology-Directed Genome Editing Using Oligonucleotide Donors

Homology-directed genome editing is the intentional alteration of an endogenous genetic locus using information from an exogenous homology donor. A conversion tract is defined as the amount of genetic information that is converted from the homology donor to a given strand of the targeted chromosomal locus. Because of this, conversion tract analysis retrospectively not only elucidates the mechanism of homology-directed genome editing but also provides valuable insights on the conversion efficiency of every nucleotide in the homology donor. Here we describe a blue fluorescent protein-to-green fluorescent protein conversion system that can be conveniently used to measure the efficiency and analyze the lengths of conversion tracts of homology-directed genome editing using oligonucleotide donors in mammalian cells.