Drosophila TAF1 as a Model for Signal-dependent Alternative Splicing

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The investigator's laboratory is interested in understanding how developmental and stress signals alter pre-mRNA splicing patterns. In metazoan organisms a majority of primary transcripts are alternatively spliced, making alternative splicing a principal mechanism for generating functional and structural diversity in proteins. Little is known about signaling events that activate or repress alternative splicing mechanisms. The laboratory has shown that alternatively spliced mRNAs of TAF1 (TBP-associated factor 1) encode proteins with different DNA-binding activities. Developmental signals during spermatogenesis direct alternative splicing of a TAF1 mRNA encoding a protein isoform that binds testis-specific promoter DNA and may activate the male germ cell-specific gene expression program. Thus, the studies of TAF1 will have a major impact on our understanding of how signaling pathways regulate alternative splicing and gene-specific transcription. The goal of the project is to understand how signaling pathways interface with the splicing machinery to regulate TAF1 alternative splicing in response to DNA damage, an event that broadly affects cell physiology. The laboratory plans to use genetic and biochemical approaches to identify the full complement of TAF1 splicing factors, and examine the extent to which TAF1 splicing factors are post-translationally modified by ATM or ATR signaling pathway enzymes in response to DNA damage. The research is significant because signal-dependent alternative splicing is likely an exceedingly common mechanism for regulating gene expression in response to changing cellular environments. However, documented examples are limited and a complete pathway has not been described. Thus, elucidation of a signal-dependent alternative splicing pathway that controls TAF1 expression will synergize with the investigator's studies of mechanisms of transcriptional regulation by TAF1 and provide a framework for experimental investigation and understanding of how signaling pathways impact expression of the multitude of genes in Drosophila and humans regulated by alternative splicing.The detailed mechanisms that underlie alternative splicing and the importance of alternative splicing for gene expression in both normal and disease states make alternative splicing a powerful educational tool that can be effectively communicated by the PI's laboratory at all instructive levels. The PI has a strong track record of providing rigorous genetic, biochemical, and molecular training for graduate, undergraduate, and high school students in the laboratory, including women and underrepresented minorities. The research results will be incorporated into a graduate level course on eukaryotic molecular biology directed by the PI. The PI will also present this work in forums that target broad scientific audiences, such as university seminars and peer-reviewed research and review articles. Thus, the research will provide opportunities to integrate research, training, and teaching.