CRISPR/Cas9-Mediated Genetic Engineering to Generate a Disease Model Prairie Vole, Based on Species-Optimized Assisted Reproductive Technology.

Social and prosocial behaviors, including communication, social bonding, and affiliation, parental behaviors, and empathy are key features of a highly social mammalian species. However, the neuronal mechanism in the brain underlying these behaviors remains unclear because of limited information on the social and prosocial behavioral levels in rodent models generally used in behavioral neuroscience studies.The rodent species, prairie vole (Microtus ochrogaster), is one of the nontraditional animal models with several advantages in experimental science over other rodent models, such as mice or rats. Additionally, it demonstrates characteristics advantageous in the study of social and prosocial behaviors, such as monogamous pair bonding behavior, biparental care, and consoling behavior toward partners stressed by aversive foot shock stimulus. Recent studies of prairie voles have highlighted the importance of oxytocin (OXT) and oxytocin receptor (OXTR)-mediated mechanisms in the regulation of these behaviors.Recently, we established assisted reproductive technologies for prairie voles, and successfully and efficiently generated an OXTR gene knockout (KO) prairie vole using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9 ), a powerful genome editing tool with artificially developed single-strand guide RNAs (sgRNA) and Cas9 endonucleases.Herein, we describe the method for CRISPR /Cas9-mediated generation of OXTR KO prairie vole. This OXTR KO prairie vole can be a valuable tool to understand their unique social and prosocial behaviors and elucidate how the oxytocin system influences or modulates these behaviors in the brain.