Synaptic vesicle depletion correlates with attenuated synaptic responses to prolonged repetitive stimulation in mice lacking alpha-synuclein.

Although the mutation of alpha-synuclein, a protein associated with presynaptic vesicles, is implicated in the etiology and pathogenesis of Parkinson's disease, the biological function of the normal protein is unknown. Mice that lack alpha-synuclein have been generated by homologous recombination in embryonic stem cells. Electron microscopic examination of hippocampal synapses revealed a striking selective deficiency of undocked vesicles without affecting docked vesicles.

Impaired conditioned fear and enhanced long-term potentiation in Fmr2 knock-out mice.

FRAXE mental retardation results from expansion and methylation of a CCG trinucleotide repeat located in exon 1 of the X-linked FMR2 gene, which results in transcriptional silencing. The product of FMR2 is a member of a family of proteins rich in serine and proline, members of which have been associated with transcriptional activation. We have developed a murine Fmr2 gene knock-out model by replacing a fragment containing parts of exon 1 and intron 1 with the Escherichia coli lacZ gene, placing lacZ under control of the Fmr2 promoter.

Knockout mouse model for Fxr2: a model for mental retardation.

Fragile X syndrome is a common form of mental retardation caused by the absence of the FMR1 protein, FMRP. Fmr1 knockout mice exhibit a phenotype with some similarities to humans, such as macro-orchidism and behavioral abnormalities. Two homologs of FMRP have been identified, FXR1P and FXR2P.