Phenotypes Associated with This Genotype

Genotype
MGI:2678317

• Allelic Composition: Klk8^tm1Shio/Klk8^tm1Shio
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6J

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

nervous system

nervous system phenotype ( J:68653 )

N • homozygotes display no significant differences in the size and overall structure of the whole brain, cerebral hemispheres, hippocampal formation, cerebellum, or brain-stem relative to wild-type mice

abnormal brain interneuron morphology ( J:68653 )

• homozygotes show a 2.7-fold increase in the number of parvalbumin-immunoreactive ("fast spiking") interneurons in the stratum oriens but not in the stratum pyramidale

abnormal hippocampus morphology ( J:68653 )

• homozygotes display significant abnormalities of synapses and neurons in the CA1 subfield of the hippocampus

• homozygotes display significant synaptic loss along with an increase of fast-spiking interneurons, indicating impaired hippocampal networking

abnormal hippocampus pyramidal cell layer ( J:68653 )

• homozygotes display an irregular stratum pyramidale, as revealed by Nissl-staining

abnormal hippocampus pyramidal cell morphology ( J:68653 )

• homozygotes exhibit significantly enlarged and elongated pyramidal cell somata, with a notable increase in long-axis cells and a reduction of typical pyramidal cells, as revealed by Golgi-Cox impregnation and Nissl-staining of pyramidal neurons in the CA1-CA3 subfields of the hippocampus

• however, no apparent changes in pyramidal cell number or in dendritic arborization and spine density are observed

• in addition, all pyramidal neurons in the CA1-CA3 subfields are functionally intact, with no apparent signs of necrosis or apoptosis

decreased CNS synapse formation ( J:68653 )

• homozygotes display a significant reduction in the number of asymmetrical synapses that contain thick postsynaptic density (PSD) in the stratum radiatum, but not in the stratum oriens

• however, no differences in synaptic morphology or sub-cellular organelle structure are observed relative to wild-type mice

abnormal GABAergic neuron morphology ( J:68653 )

• homozygotes show a 2.7-fold increase in the number of parvalbumin-immunoreactive ("fast spiking") interneurons, which co-express GABA and are thought to be involved in hippocampal oscillation

abnormal synaptic bouton morphology ( J:68653 )

• homozygotes show a significant decrease of synaptic boutons in the CA1 subfield in the stratum radiatum, along with a marked increase in free boutons in both the strata radiatum and oriens

• although the total number of synaptic and free boutons remains relatively unchanged, the % of synaptic boutons and free boutons is significantly decreased and increased, respectively