Genome Editing

About

Brief Description: Easily accessible and efficient methodologies to edit the genomes of organisms are an immense resource to the biological and biomedical research community. Traditionally, engineering of the mammalian genome is achieved by homologous recombination (HR)-mediated sequence substitution in embryonic stem cells (ESCs), a time consuming process that occurs at low frequency. Taking genetically engineering in mice for example, after extensive screening for ESC colonies with the desired genetic modifications, ESCs are microinjected into mouse blastocysts to generate chimeras capable of germline transmission. Such chimera mice are then crossed to wild-type mice to generate heterozygous offspring (F1), which are then intercrossed to yield homozygous mutant mice (F2) that can be subjected to phenotypic analyses. Despite the wide use of this technology to generate transgenic mice, the low efficiency of HR in ESCs, the laborious process of screening, the technical difficulty of microinjection, and the nature of the mouse life cycle make this approach a lengthy and costly process.   UC Berkeley researchers developed methods for modifying the genome of a mammalian zygote by introducing a ribonucleoprotein complex (RNP) to the zygote via electroporation.  Suitable genome editing nucleases were found to be CRISPR/Cas endonucleases (e.g., class 2 CRISPR/Cas endonucleases such as a type II, type V, or type VI CRISPR/Cas endonucleases.   Suggested Uses: genome editing in mammalian zygotes modulating transcription in mammalian zygotes research tools   Advantages: faster, more efficient editing uses commonly available reagents and equipment to deliver RNP into mouse zygotes embryos were edited by non-homologous end joining  with up to 100% efficiency, improved the embryo viability can be easily applied to other mammalian species.