Stereotaxic Surgery as a Method to Deliver Epigenetic Editing Constructs in Rodent Brain

Modern neuroscience research is increasingly discovering that alterations in epigenetic states within key brain cells is correlated with brain diseases. These epigenetic alterations may include changes in histone post-translational modifications and/or DNA modifications, all of which affect transcription and other gene expression programs within the brain cells that comprise central brain regions. However, the exact causal contribution of these epigenome changes to brain disease cannot be elucidated in the absence of direct in vivo manipulations in the implicated brain areas. Combining the design and creation of epigenetic editing constructs, gene delivery strategies, and stereotaxic surgery enables neuroscience researchers to target and manipulate the epigenetic state of the brain cells of laboratory rodents in a locus-specific manner and test its causal contribution to disease-related pathology and behaviors. Here, we describe the surgical protocol utilized by our group and others, which is optimized for herpes simplex virus delivery into the mouse brain, although the protocol outlined herein could be applied for delivery of adeno-associated viruses, lentiviruses, or nonviral gene-delivery methods in both mice and rats. The method allows for the overexpression of engineered DNA-binding proteins for direct and targeted epigenome editing in rodent brain with excellent spatiotemporal control. Nearly any brain region of interest can be targeted in rodents at every stage of postnatal life. Owing to the versatility, reproducibility, and utility of this technique, it is an important method for any laboratory interested in studying the cellular, circuit, and behavioral consequences of manipulating the brain epigenome in laboratory rodents.