This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Research project. At the heart of each eukaryotic cell is the nucleus, a complex structure highly organized into many distinct functional domains to perform two fundamental roles: the maintenance of the genome and the distribution of the genetic information. Among the sub-nuclear domains are the sites where genes are transcribed into pre-messenger RNA (pre-mRNA) molecules. As they are being synthesized, pre-mRNAs undergo a series of complex processing events to produce the messenger RNAs that are subsequently used for the synthesis of proteins. One of these events, splicing, requires the five major small ribonucleoprotein particles (snRNPs). Despite the critical catalytic role of snRNPs in splicing, little is still known about the cellular mechanisms that regulate their recruitment to pre-mRNAs. This program aims at moving the analysis of snRNPs to the amphibian oocyte, a unique cell system where direct visualization of individual transcription sites and other sub-nuclear domains is possible in the transmitted light microscope. The main objective, using this in vivo system, is to determine the characteristic elements of snRNPs required for their interactions with pre-mRNAs and their co-transcriptional splicing activity. In frog oocytes, the sites of active transcription correspond to the lateral loops of the lampbrush chromosomes (LBCs). The research is based on two newly developed assays, which permits one to follow the association of snRNPs with the lateral loops of LBCs and to determine whether pre-mRNA splicing occurs on these loops, respectively. In the long term, these studies will contribute to the general understanding of the cellular mechanisms that govern the functional organization of an active transcription unit, and how various subnuclear domains interact to regulate pre-mRNA processing.
Broader Impacts. The giant size of an amphibian oocyte and its ease of manipulation make it particularly amenable to an active outreach program. Indeed, showing chromosomes and genes being actively transcribed in a fluorescence microscope to students of all levels (undergraduate and highschool) always succeeds at capturing their interest, while introducing them to the principles of experimental science. The investigator will use the research to continue fostering relations with teachers at neighboring high schools and community colleges, contributing to the development of strong curricula and providing their students, including women and minorities, with research internships. The goal is to provide teachers with scientific support and to expose students to research in an academic setting, while facilitating their transition from small high schools and community colleges to large undergraduate campuses.
