RT Journal Article
SR Electronic
T1 Presynaptic <em>Fmr1</em> Genotype Influences the Degree of Synaptic Connectivity in a Mosaic Mouse Model of Fragile X Syndrome
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4014
OP 4018
DO 10.1523/JNEUROSCI.4717-06.2007
VO 27
IS 15
A1 Hanson, Jesse E.
A1 Madison, Daniel V.
YR 2007
UL http://www.jneurosci.org/content/27/15/4014.abstract
AB Almost all female and some male fragile X syndrome (FXS) patients are mosaic for expression of the FMR1 gene, yet all research in models of FXS has been in animals uniformly lacking Fmr1 expression. Therefore, we developed a system allowing neuronal genotype to be visualized in vitro in mouse brain slices mosaic for Fmr1 expression. Whole-cell recordings from individual pairs of presynaptic and postsynaptic neurons in organotypic hippocampal slices were used to probe the cell-autonomous effects of Fmr1 genotype in mosaic networks. These recordings revealed that wild-type presynaptic neurons formed synaptic connections at a greater rate than presynaptic neurons lacking normal Fmr1 function in mosaic networks. At the same time, the postsynaptic Fmr1 genotype did not influence the probability that a neuron received synaptic connections. Asymmetric presynaptic function during development of the brain could result in a decreased participation in network function by the portion of neurons lacking FMR1 expression.