Intellectual Merit: A complex network of regulatory proteins functions in eukaryotic cells to ensure that normal RNAs accumulate at the appropriate levels and that aberrant or potentially harmful RNAs are not expressed. The deleterious effects of transposable DNA elements are kept in check through surveillance pathways that function at various steps in RNA metabolism to block expression of transposon-encoded RNAs. Suppressor of sable protein [Su(s)] of Drosophila melanogaster is a component of a nuclear regulatory process that inhibits the accumulation of transposon-containing RNAs, such as those produced by alpha-beta retrotransposons located in the vicinity of heat-shock induced Hsp70 genes. The goal of this project is to learn more about this regulation and the specific role that Su(s) plays in inhibiting alpha-beta and other RNAs. Prior research indicates that Su(s) functions co-transcriptionally and interacts with Wdr82/Swd2, a multifunctional protein that has been shown by other labs to reside in at least two distinct complexes. One Wdr82/Swd2-containing complex regulates a particular chromatin modification (H3K4 methylation) in yeast and mammals. The other complex regulates 3' end processing and transcription termination at small nucleolar RNA genes in yeast. The main objective of the current research is to determine whether the activity of Su(s)/Wdr82 is related to one of the known Wdr82 functions or a different process. Thus, two hypotheses, which are not mutually exclusive, will be tested. The first hypothesis is that Su(s) and Wdr82 are recruited to the heat shock locus during heat stress and induce a chromatin modification that inhibits alpha-beta RNA accumulation. The second hypothesis is that Su(s), which is known to be an RNA-binding protein, binds directly to regulatory sequences in alpha-beta RNA and induces transcriptional stalling/termination or nascent RNA cleavage. Other experiments will map the Wdr82-interaction domain within Su(s). A multifaceted approach will be employed in this research, including chromatin immunoprecipitation analysis, polytene chromosome immunofluorescence analysis, reporter gene expression studies, in vitro RNA cleavage assays, and protein-protein interaction analysis.
Broader Impacts: The results obtained from this research will advance the understanding of regulatory mechanisms that minimize the deleterious and mutagenic effects of transposons in multicellular organisms. In addition, this research is making a significant contribution to the development of human resources in science, as this ongoing project has supported and continues to support the training of numerous graduate and undergraduate students. Throughout her career the PI has been active in efforts at multiple levels--within her lab, the university, and beyond--to promote the participation and success of underrepresented groups in scientific research and academia. The PI also plays a leadership role in programs designed to enhance the academic success of undergraduate science majors and their participation in undergraduate research.
