2018 Theses Doctoral

Regulation of splicing networks in neurodevelopment

Weyn-Vanhentenryck, Sabastien Matthieu

Alternative splicing of pre-mRNA is a critical mechanism for enabling genetic diversity, and is a carefully regulated process in neuronal differentiation. RNA binding proteins (RBPs) are developmentally expressed and physically interact with RNA to drive specific splicing changes. This work tests the hypothesis that RBP-RNA interactions are critical for regulating timed and coordinated alternative splicing changes during neurodevelopment and that these splicing changes are in turn part of major regulatory mechanisms that underlie morphological and functional maturation of neurons. I describe our efforts to identify functional RBP-RNA interactions, including the identification of previously unobserved splicing events, and explore the combinatorial roles of multiple brain-specific RBPs during development. Using integrative modeling that combines multiple sources of data, we find hundreds of regulated splicing events for each of RBFOX, NOVA, PTBP, and MBNL. In the neurodevelopmental context, we find that the proteins control different sets of exons, with RBFOX, NOVA, and PTBP regulating early splicing changes and MBNL largely regulating later splicing changes. These findings additionally led to the observation that CNS and sensory neurons express a variety of different RBP programs, with many sensory neurons expressing a less mature splicing pattern than CNS neurons. We also establish a foundation for further exploration of neurodevelopmental splicing, by investigating the regulation of previously unobserved splicing events.