Methylation-induced transcriptional silencing of the fragile X mental retardation-1 (Fmr1) gene leads to absence of the gene product, fragile X mental retardation protein (FMRP), and consequently fragile X syndrome (FrX), an X-linked inherited form of mental retardation. Absence of FMRP in Fmr1 null mice imparts some characteristics of the FrX phenotype, but the precise role of FMRP in neuronal...

UNLABELLED An increasing body of evidence indicates that astrocytes contribute to the governance and fine tuning of stem and progenitor cell production during brain development. The effect of astrocyte function in cell production in neurodevelopmental disorders is unknown. We used the Neural Colony Forming Cell assay to determine the effect of astrocyte conditioned media (ACM) on the generation...

Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a progressive neurodegenerative disorder that has been diagnosed in a substantial fraction of older male fragile X premutation carriers. Patients affected by FXTAS have elevated levels of ribo-rCGG repeat containing FMR1 mRNA with normal to slightly reduced levels of FMRP in blood leukocytes. Coupled with the absence of FXTAS in fragile X s...

Fragile X syndrome (FXS) is characterized by intellectual disability and autistic traits, and results from the silencing of the FMR1 gene coding for a protein implicated in the regulation of protein synthesis at synapses. The lack of functional Fragile X mental retardation protein has been proposed to result in an excessive signaling of synaptic metabotropic glutamate receptors, leading to alte...

Despite extensive research into both synaptic and morphological changes, surprisingly little is known about dendritic function in fragile X syndrome (FXS). We found that the dendritic input resistance of CA1 neurons was significantly lower in fmr1(-/y) versus wild-type mice. Consistent with elevated dendritic I(h), voltage sag, rebound, and resonance frequency were significantly higher and temp...

Fragile X Syndrome is a leading heritable cause of mental retardation that results from the loss of FMR1 gene function. Studies in mouse and Drosophila model organisms have been critical in understanding many aspects of the loss of function of the FMR1 gene in the human syndrome. Here, we establish that the zebrafish is a useful model organism for the study of the human fragile X syndrome and c...

The fragile X mental retardation 1 gene (FMR1), which codes for the fragile X mental retardation 1 protein (FMRP), is located at Xp27.3. The normal allele of the FMR1 gene typically has 5 to 40 CGG repeats in the 5' untranslated region; abnormal alleles of dynamic mutations include the full mutation (> 200 CGG repeats), premutation (55-200 CGG repeats) and the gray zone mutation (45-54 CGG repe...

Fragile X syndrome, the most common form of inherited mental retardation is caused by silencing of the Fmr1 (fragile x mental retardation-1) gene. Two mammalian homologues of Fmr1 have been identified: fragile X-related Protein 1 (Fxr1) and Protein 2Fxr2. Aberrations in dendritic spines of Fragile X syndrome patients and Fmr1 null mice implicate FMRP in synapse fo rmation and function. However,...

Fragile X-associated Tremor/Ataxia syndrome (FXTAS), a late-onset monogenetic neurodegenerative disorder, is caused by a CGG-repeat expansion (55-200) in the 5′ UTR of the fragile-X mental retardation 1 gene (FMR1) on the X-chromosome [1]. The prevalence of the FMR1 premutation (PM) is about 1:855 in males and 1:291 in females [2]. Approximately 45.5% of male and 16.5% of female PM carriers old...

Fragile X syndrome is one of the most common genetic causes of mental retardation, yet the mechanisms controlling expression of the fragile X mental retardation gene FMR1 are poorly understood. To identify sequences regulating FMR1 transcription, transgenic mouse lines were established using a fusion gene consisting of an E.coli beta-galactosidase reporter gene (lacZ) linked to a 2.8 kb fragmen...