Speaker: Fernando Bustos, Ph.D.
Affiliation: Simons Postdoctoral Fellow, Martha Constantine-Paton Lab, McGovern Institute for Brain Research, MIT

Talk Title: Use of CRISPRs to Remove a Spontaneous Mouse Mutation Causing Abnormal Anxiety- /Autism-like Behaviors
Abstract: Recombination events in the genome occur frequently and can alter genome architecture producing devastating genetic disorders. Many of these occur because of duplications or fusions of genomic sequences that cause an extra gene to be expressed (e.g. Charcot-Marie-Tooth disease, MeCP2 duplication, etc). I am studying a mouse model in which a recombination event produced an extra gene composed by the fusion in frame of portions of gnb5 and myo5a genes. This extra gene named flailer causes defects in synapse formation and exhibits an anxiety/autistic phenotype. This defect is due to the ability of Flailer to work as a dominant negative of MyoVa, limiting the transport of synaptic components (e.g. PSD95, Shank, endoplasmic reticulum, etc.) to the synapse. My goal is to specifically remove the flailer gene thus recovering the synaptic defects and behaviors, and also to identify the particular brain areas that are involved in the anxiety/autism phenotype. In order to do this, we turned to Double-Nicking-CRISPRs to specifically modify the flailer gene without altering the endogenous copies of gnb5 or moy5a that remain intact in the genome.

We were able to modify ~700bp of the flailer gene causing the disruption of the gene. Modified neurons show the reversal of the synaptic defects in which clustering of PSD95, calcium transients and mEPSC are recovered.

This same approach used to recover the synaptic defects caused by flailer, could be applied to target other diseases in which duplications or recombination events exist, and there is a need to remove the mutated genes without altering the WT genomic sequence.