Development of Knockout Cardiac Muscle Cell Lines Using Integrase-Deficient Lentivirus-Mediated CRISPR/Cas9 Gene Editing.

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) gene editing technology is a highly efficient genome editing tool that can genetically disrupt genes and genetic elements, making it a timely, cost-effective, and powerful tool for studying gene function. The success of gene editing depends on the ability to introduce CRISPR components, including guide RNA (gRNA) and Cas9 nuclease, into the target cell, which is challenging in numerous difficult-to-transfect cell types, such as cardiomyocytes. Lentiviral vectors (LVs) are among the primary delivery methods for the CRISPR/Cas9 system as they can stably maintain robust expression in various dividing and non-dividing cells. However, stably integrated LVs consistently express CRISPR/Cas9 components at high levels, rendering them susceptible to off-target effects. New-generation integrase-deficient LV (IDLV) offers an attractive alternative approach for delivering CRISPR/Cas9 components. This study constructed transient receptor potential cation channel mucolipin subfamily member 1 gene knockout models in H9C2 cell lines using IDLVs. Strategies for gRNA design and screening, the IDLV packaging process, CRISPR delivery, and knockout validation are outlined. These protocols will assist researchers in the application of CRISPR technology to study gene function in mammalian cells.