Phenotypes associated with this allele

• Allele Symbol: Ckb^tm1Bew
• Allele Name: targeted mutation 1, Be Wieringa
• Allele ID: MGI:3042843
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Ckb^tm1Bew/Ckb^tm1Bew	involves: 129P/Ola * C57BL/6	MGI:3042845
cx2	Ckb^tm1Bew/Ckb^tm1Bew Ckmt1^tm2Bew/Ckmt1^tm2Bew	involves: 129P2/OlaHsd * C57BL/6	MGI:3693851

Genotype
MGI:3042845

hm1

• Allelic Composition: Ckb^tm1Bew/Ckb^tm1Bew
• Genetic Background: involves: 129P/Ola * C57BL/6

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

behavior/neurological

decreased susceptibility to pharmacologically induced seizures ( J:89399 )

• homozygous mutants need significantly more pentylenetetrazole to induce seizures

• homozygous mutants display more preseizure myoclonic jerks compared to wild-type mice

increased exploration in new environment ( J:89399 )

• homozygous mutants are more active 20 and 30 minutes into an open-field test compared to wild-type mice

• in the open-field test, homozygotes remain hyperactive with little sitting and grooming, and none of them exhibit the formation of a home base, suggesting diminished habituation

abnormal spatial learning ( J:89399 )

• homozygous mutants take longer to find a submerged platform compared to wild-type mice

nervous system

decreased susceptibility to pharmacologically induced seizures ( J:89399 )

• homozygous mutants need significantly more pentylenetetrazole to induce seizures

• homozygous mutants display more preseizure myoclonic jerks compared to wild-type mice

abnormal hippocampal mossy fiber morphology ( J:89399 )

• the intra- and infrapyramidal mossy fiber area is enlarged in homozygous mutants compared to wild-type mice

Genotype
MGI:3693851

cx2

• Allelic Composition: Ckb^tm1Bew/Ckb^tm1Bew; Ckmt1^tm2Bew/Ckmt1^tm2Bew
• Genetic Background: involves: 129P2/OlaHsd * C57BL/6

behavior/neurological

abnormal spatial learning ( J:95227 )

• double homozygotes exhibit impaired spatial learning in the Morris water maze, with significantly higher escape latencies in the acquisition phase, and a non-specific searching performance in the probe trial relative to wild-type mice

• double homozygotes show impaired spatial learning in a circular hole board dry maze, with significantly higher escape latencies, more errors during the effort to find an escape hole, and a non-specific searching performance in the probe trial relative to wild-type mice

• however, no visual or motor deficiencies are detected in the water maze visual platform swimming task or rotarod task, respectively

• also, no differences in open field exploration and habituation, spontaneous alternation behavior in the T-maze task or anxiety-related responses in the light-dark box are observed

decreased startle reflex ( J:95227 )

• similar to single homozygotes, double homozygotes show a 4-fold reduction in startle responses, confirmed by the acoustic startle profile using stimuli in the range of 70-150 dB

• however, in response to a 86 dB prepulse, double homozygotes show an inhibition response that is only 14 db higher than the threshold prepulse of 72 dB, indicating normal hearing

abnormal nest building behavior ( J:95227 )

• double homozygotes display a 4-fold reduction in nest building activity relative to wild-type mice

growth/size/body

decreased body weight ( J:95227 )

• at 3 months, both male and female double homozygotes display a reduced average body weight relative to wild-type counterparts

• at 4-10 months, double homozygotes weight 18-20% less than wild-type counterparts

postnatal growth retardation ( J:95227 )

• starting at P7, both male and female double homozygotes gain weight more slowly relative to wild-type counterparts

nervous system

decreased brain size ( J:95227 )

decreased brain weight ( J:95227 )

• double homozygotes show a ~6.3% reduction in wet brain weight relative to wild-type mice

abnormal hippocampal mossy fiber morphology ( J:95227 )

• double homozygotes show a ~15% size reduction in the hippocampus/regio-inferior (CA3 area plus hilus) area relative to wild-type mice

• as a result, the relative size of the supra-pyramidal mossy fiber area is significantly enlarged relative to that of wild-type mice

• the relative size of the intra-infra-pyramidal mossy fiber area is also enlarged, but this does not reach statistical significance

small hippocampus ( J:95227 )

• double homozygotes show a 7% size reduction in the hippocampus relative to wild-type mice