A Rapid and Highly Efficient Genotyping Pipeline for Screening Gene Targeted Mouse Embryonic Stem Cells

Abstract Gene targeting in mouse ES cells replaces or modifies genes of interest; conditional alleles, reporter knock-ins, and amino acid changes are common examples of how gene targeting is used. For example, enhanced green fluorescent protein or Cre recombinase is placed under the control of endogenous genes to define promoter expression patterns. The most important step in the process is to demonstrate that a gene targeting vector is correctly integrated in the genome at the desired chromosomal location. The rapid identification of correctly targeted ES cell clones is facilitated by proper targeting vector construction, rapid screening procedures, and advances in cell culture. The addition of magnetic activated cell sorting (MACS) technology and multiplex droplet digital PCR (ddPCR) to the ES cell screening process can achieve a greater than 60% assurance that ES clones are correctly targeted. In a further refinement of the process, drug selection cassettes are removed from ES cells with adenovirus technology. This improved workflow reduces the time needed to generate preclinical animal models. Faster access to animal models for therapeutic target identification and experimental validation can accelerate the development of therapies for human disease.