Molecular Mechanisms of Visual Pathway Plasticity\n

Molecular Mechanisms of Visual Pathway Plasticity
We use a multidisciplinary approach involving biochemistry and immunoprecipitation, immunocytochemistry and vital imaging in tissue culture to identify and study the signaling molecules that are associated with the glutamate receptors in the "eye opening interval". We have also begun to collaborate with the Broad Institute Proteomics Units headed by Dr. Steven Carr. We are using liquid chromatography and tandem mass spectroscopy (LCMs/MS) to identify the protein changes in visual cortex post-synaptic densities across the eye opening and juvenile to adult intervals and we are using lentiviral vectors to express in vivo in neonate rat visual centers short inhibitory RNA molecules (siRNA) against molecules suspected of involvement in these processes. Other experiments utilize mutant mouse strains to determine whether the trafficking of NMDA receptors and/or the specific NR2A versus NR2B subunits or the receptor scaffolds and signaling modules are requuired for the plasticity observed after eye opening. Finally we are in the middle of two large gene chip experiments with mRNAs from the visual layers of the superior collciulus before, and after, eye opening and from litter mates in which eye are never opened. This has allowed us to factor out changes in gene expression due to eye opening from changes due merely to age. The one completed analysis has suggested several very interesting molecules that are good candidates for siRNA knockdown studies, again in vivo, to test the requirement for these gene products during eye opening induced plasticity. We have an additional ongoing study in which microRNAs that change in the eye opening interval are being compared to transcripts that change in the same interval to determined if any of the synaptic plasticity events are under the control of microRNA.