Date of Award
Doctor of Philosophy (PhD)
Darnell Robert Laboratory
Nova-1 is a neuron-specific RNA binding protein, distributed both in the nucleus and the cytoplasm of several populations of neurons. The work presented here confirms that Nova-1 binds a sequence of RNA found in an intron of the glycine receptor a2 subunit pre-mRNA. Evidence that Nova-1 acts as a regulator of alternative splicing in transfected cell lines is presented. Furthermore, a direct role of Nova-1 on splicing is demonstrated by establishing an in vitro assay for Nova-l's regulatory role in splicing. Potential functional partners of Nova are suggested by the demonstration of physical interactions between Nova-1 and molecules whose action in the splicing machinery is well described, such as Ul 70K, a protein component of UlsnRNP, and U2AF65. The sedimentation properties of Nova in neuronal cytoplasmic extracts are consistent with the engagement of Nova in heterogeneous structures, probably mRNPs, and with polysomes, suggesting a role for Nova in the regulation of cytoplasmic phenomena of RNA metabolism, such as mRNA localization and translation. These considerations prompted a gene expression screen aimed to identify differences in the pool of mRNAs associated with heavy polysomes in wild type and Nova-1-null mice. Several genes whose mRNAs have been found to undergo changes in abundance specifically in the polysome fraction in the absence of Nova have described functional roles in post-synaptic terminal structure and functions. Nova-1 was also found to be a phospho-protein, and phosphorylation site is in an alternative cassette exon.
Stefani, Giovanni, "Functional Roles of Nova in RNA Metabolism" (2003). Student Theses and Dissertations. 326.