External Seminar Uncovering post-transcriptional regulatory mechanisms underling nervous system development and disorders through CRISPR-based screening strategies Seminar details October 1, 2018, 1:00 pm @ Murray Seminar Room Dr. Thomas Gonatopoulos-Pournatzis, Donnelly Centre, University of Toronto Host: Vicky Cowling Abstract Alternative splicing (AS) plays critical roles in the control of nervous system development and function and is implicated in numerous neurological disorders. However, the functional complexity of AS in neurons is poorly understood. Accordingly, an overarching challenge is to systematically identify functionally important alternative exons and to develop a comprehensive knowledge of the regulatory networks that control these exons. I will present the systematic exploration of factors and pathways that control splicing by developing a genome-wide CRISPR-based screening strategy. Application of this approach to a micro-exon network revealed a specialized mechanism for the recognition and splicing of very short exons in neurons. Furthermore, I will describe the identification of a neuron-specific micro-exon in the translation initiation factor EIF4G. This exon controls the functional specialization of the translational machinery and regulates the expression of synaptic receptors impacting neuronal activity and higher order cognitive functions. Finally, I will present the development of a novel CRISPR dual-guide screening platform that allows efficient combinatorial genetic targeting and as such paves the way for functional genetic screens with single-exon resolution.