Our lab is interested in the regulation of pre-mRNA splicing and the biochemical mechanisms that control changes in splice sites. The sequences of metazoan genomes, with their relatively low gene numbers, have highlighted the question of how protein number can be expanded beyond the gene number for a complex organism. Alternative splicing, which allows the production of multiple mRNAs and hence multiple proteins from a single gene, is a major contributor to protein diversity. However, despite its key role in gene expression, this process is poorly understood mechanistically.
Alternative splicing is particularly common in genes expressed in the mammalian nervous system, where many proteins important for neuronal differentiation and function are made in diverse isoforms through controlled changes in splicing. Our lab works on a range of projects related to the control of pre-mRNA splicing in neurons. We aim to determine the mechanisms of action of splicing regulators, as well as to understand their roles in neural development and mature neuronal function.
We are focused on four regulatory factors: polypyrimidine tract–binding protein (PTB, PTBP1), neuronal PTB (nPTB, brPTB, PTBP2), Fox-1 (also called A2BP1), and Fox-2 (also called RBM9). Each of these proteins alters the splicing of a specific set of exons within the genome, and each can act to enhance splicing in some contexts but repress it in others. In mechanistic studies, we use in vitro splicing systems to examine the RNA-binding properties of these proteins and analyze how they can alter spliceosome assembly. In a second effort, we use cell culture models and conditional knockout mice to understand how these proteins affect neuronal development. In a third area of study, we focus on the effect of cell excitation on the splicing of ion channel transcripts and the role of this splicing in neuronal plasticity. Finally, we have a project to identify small molecules that alter the splicing of particular exons affecting neurological disease. The molecules identified in these screens are being used as tools to study alternative splicing regulation and are being assessed as candidates for drug therapies.