Neuron-specific alternative polyadenylation in nervous system development and function

• Applicant: Dr. Valerie Hilgers
• Subject Area: Developmental Biology
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259199801

The 3’ termini of metazoan mRNAs determine transcript stability, translation efficiency, and subcellular localization. We recently found that a subset of developmental regulatory genes exhibit synchronous lengthening of their 3’ untranslated region (UTR) during the course of Drosophila embryogenesis. Notably, these extended 3’ UTR sequences are selectively expressed in neural tissues (Hilgers et al., 2011). We found that the pan-neuronal RNA-binding protein ELAV coordinates 3’ extension by binding to proximal polyadenylation (poly(A)) signals and inhibiting processing at that site (Hilgers et al., 2012). Recent studies in zebrafish and mouse suggest that 3’ UTR extensions are a conserved feature of neurogenesis in vertebrates (Ulitsky et al., 2012; Miura et al., 2013). The function of these exceptionally long UTR sequences is currently unknown. The unique, neural-specific 3’ extensions might render the mRNAs susceptible to complex regulation, including interactions with microRNAs and RNA-binding proteins. I will exploit the sophisticated genetic manipulations available in Drosophila to test this hypothesis and determine the function of 3’ extensions in vivo. I have generated mutant flies specifically lacking the 3’ UTR extensions of ago1 and elav. These flies will be analyzed using biochemical methods, highresolution mRNA visualization, behavioral assays as well as whole genome transcriptome studies. Moreover, my most recent work suggests that the suppression of proximal poly(A) signals involves association of ELAV with the transcription initiation machinery, implying a direct regulatory feedback between transcription initiation and termination. In order to gain mechanistic insight into the regulation of 3’ extension synthesis, I will use Drosophila transgenesis and wholegenome analysis of immunoprecipitates of RNA and DNA bound to ELAV.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Michael Levine