|About GSBS | FAQ | Job Opportunities | Search UMDNJ|
Department of Microbiology and Molecular Genetics
B. Sc. 2003, Panjab University, India
M. Sc. 2005, Panjab University, India
Thesis Advisor: Sanjay Tyagi, Ph.D.
Public Health Research Institute
Tuesday, August 23, 2011
ICPH Auditorium, 1:00 P.M.
The process of Long Term Potentiation (LTP) in the hippocampus, which serves as model for memory formation, requires local protein synthesis at the sites of the active synapses. RNA transport granules deliver translationally repressed mRNAs to synaptic sites in dendrites, where synaptic activity promotes their localized translation. The transport and local translation of mRNAs only at the activated synapses is crucial for the maintenance of LTP. Although the identities of many proteins that make up the transport granules are known, the stoichiometry of their core component, the mRNA, is poorly understood. Imaging nine different dendritically localized mRNA species with single-molecule sensitivity and sub-diffraction-limit resolution in cultured hippocampal neurons, we show that there is just one molecule of mRNA in each RNA granule. Even mRNA species that possess a common dendritic localization element, a sequence that is believed to mediate the incorporation of that mRNA into a transport granule, are segregated into separate granules. By contrast, even though single-molecule imaging confirmed the solitary presence of neuronal mRNAs in transport granules, the same technique showed that multiple oskar mRNA molecules are present within individual transport granules that deliver that mRNA to the posterior tip of Drosophila oocytes. These results support a model in which mRNA molecules are transported to distal reaches of dendrites singly, and independent of other mRNAs, thereby enabling a finer control of mRNA content within synapses.