Phenotypes Associated with This Genotype

Genotype
MGI:5800332

• Allelic Composition: Lrfn4^{tm1(KOMP)Vlcg}/Lrfn4^{tm1(KOMP)Vlcg}
• Genetic Background: involves: C57BL/6J * C57BL/6NTac
• Cell Lines: 10115A-A9

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

nervous system

abnormal excitatory synapse morphology ( J:233980 )

• at P14, mice show a ~14.5% decrease in the density of excitatory synapses (i.e. sites of postsynaptic density (PSD) apposed to axon terminals) in the hippocampal CA1 region (stratum radiatum) relative to wild-type controls

• a similar reduction is noted in the density of PSDs apposed to axon terminals immunopositive for glutamate in the stratum radiatum

• however, PSD perforation (a measure of excitatory synaptic maturity), thickness, and length are normal

abnormal miniature excitatory postsynaptic currents ( J:233980 )

• at P17-P21, mice show a ~52.3% reduction in the frequency, but not amplitude, of miniature excitatory postsynaptic currents (mEPSCs) in hippocampal CA1 pyramidal neurons relative to wild-type controls

• in contrast, both the frequency and amplitude of mEPSCs are normal in dorsolateral striatal neurons at P17-19

• neither the frequency nor amplitude of miniature inhibitory postsynaptic currents (mIPSCs) is altered

• both paired pulse facilitation (3-4 weeks) and AMPA-NMDA ratio (based on AMPAR and NMDAR EPSCs at 2-3 weeks) are normal at SC-CA1 synapses, indicating normal excitatory synaptic transmission

• no differences are noted in LTP induced by theta burst stimulation, in LTD induced by low-frequency stimulation, or in late LTP induced by three trains of high-frequency stimulation at SC-CA1 synapses relative to wild-type controls, indicating normal synaptic plasticity

behavior/neurological

behavior/neurological phenotype ( J:233980 )

N • at 2-5 months of age, mice exhibit normal anxiety-like behavior, motor coordination, and stereotypic behaviors (grooming and digging) relative to wild-type controls

N • mice show normal hippocampus-dependent learning and memory in T-maze, Morris water maze, novel object recognition, and contextual fear conditioning and extinction tests

behavioral arrest ( J:233980 )

• mice exhibit an increased frequency of immobility in an open field assay, suggesting that frequent episodes of immobility contribute to hypoactivity

• however, the duration of each immobility episode is normal

decreased locomotor activity ( J:233980 )

• at 2-5 months of age, mice exhibit hypoactivity in a novel environment, as measured by the total distance moved in an open field arena relative to wild-type controls

• mice are also hypoactive in a familiar environment (home cage), esp. during the first half of the light-off period