A fundamental problem in neuroscience is understanding how ephemeral episodes of experience are transformed into stable changes in synaptic architecture and efficacy. The creation of such long-lasting synaptic modifications requires new protein synthesis, which in turn is regulated at both transcriptional and translational levels. Moreover, the transcriptional profile of the neuron is a function of its developmental stage - e.g. critical period - and its history of activation. A major challenge in unraveling the mechanisms of long term plasticity then is to relate both developmental timing and experience-induced neural activity to the regulation of identified molecules that play key roles in synaptic plasticity. Fragile X Syndrome (FXS) offers a portal to the heart of this problem. FXS affects about 1:4000 boys and is caused by a triplet repeat expansion and hypermethylation of the Fmr1 promoter, leading to gene silencing. The protein product of the Fmr1 gene, FMRP, plays a central role in regulating protein synthesis-dependent synaptic plasticity. Our laboratory has established in vivo and cell culture systems for the study of Fmr1 transcription and expression. We find that Fmr1 transcripts are highly abundant in the developing and adult olfactory bulb and are bi-directionally regulated by olfactory experience. Preliminary in vivo and ce|l culture studies have provided evidence for two molecular mechanisms that regulate Fmr1 transcription: the transcription factor AP-2a and the selective, developmentally-regulated epigenetic modification of the Fmr1 gene regulatory regions. In the proposed studies we will use the olfactory system together with genetic and cell culture models to elucidate the molecular logic of Fmr1 gene regulation in the intact CNS.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD052083-05
Application #
7840379
Study Section
Special Emphasis Panel (ZRG1-MDCN-L (04))
Program Officer
Urv, Tiina K
Project Start
2006-07-01
Project End
2012-04-30
Budget Start
2010-05-01
Budget End
2012-04-30
Support Year
5
Fiscal Year
2010
Total Cost
$255,627
Indirect Cost
Name
Brown University
Department
Neurosciences
Type
Schools of Medicine
DUNS #
001785542
City
Providence
State
RI
Country
United States
Zip Code
02912
Akins, Michael R; Berk-Rauch, Hanna E; Kwan, Kenneth Y et al. (2017) Axonal ribosomes and mRNAs associate with fragile X granules in adult rodent and human brains. Hum Mol Genet 26:192-209
Stackpole, Emily E; Akins, Michael R; Fallon, Justin R (2014) N-myristoylation regulates the axonal distribution of the Fragile X-related protein FXR2P. Mol Cell Neurosci 62:42-50
Akins, Michael R; Leblanc, Hannah F; Stackpole, Emily E et al. (2012) Systematic mapping of fragile X granules in the mouse brain reveals a potential role for presynaptic FMRP in sensorimotor functions. J Comp Neurol 520:3687-706
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Christie, Sean B; Akins, Michael R; Schwob, James E et al. (2009) The FXG: a presynaptic fragile X granule expressed in a subset of developing brain circuits. J Neurosci 29:1514-24
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