A Platform for Reverse Genetics in Endothelial Cells

The recent development of programmable nucleases has the potential to revolutionize biological sciences. In particular, the Cas9 nuclease, which functions as a component of the clustered regularly interspaced short palindromic repeats (CRISPR) system in bacteria,1 has proven to be a highly efficient tool for genome editing in a wide range of model organisms, including mouse, zebrafish, Drosophila , and Caenorhabditis elegans .2–5 Application of Cas9 also allows straightforward genetic manipulations in cultured cells and is efficient enough to perform genome-wide screens in cell lines.6,7 However, applying genome editing tools in this manner in vascular biology is challenging because of the widespread use of primary cell cultures, which have a limited lifespan and are difficult to use for clonal analysis. Fortunately, studies by Abrahimi et al in this issue describe several solutions that facilitate the application of Cas9 in cultured endothelial cells. Together, these technical advances provide a valuable platform to enable straightforward and robust reverse genetic analysis in endothelial cells. Article, see p 121 The discovery of RNA interference8 and its derived or related applications (eg, short hairpin RNAs and small interfering RNAs) revolutionized the analysis of gene function in both model organisms and cell culture.9 However, these approaches often only partially decrease gene function and can have widespread off-target effects leading to false-positives.10 Accordingly, Abrahimi et al chose to apply a more definitive genetic approach by directly introducing targeted deletions into …