Phenotypes associated with this allele

• Allele Symbol: Ckmt1^tm2Bew
• Allele Name: targeted mutation 2, Be Wieringa
• Allele ID: MGI:2180567
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Ckmt1^tm2Bew/Ckmt1^tm2Bew	involves: 129P2/OlaHsd * C57BL/6	MGI:2663248
cx2	Ckb^tm1Bew/Ckb^tm1Bew Ckmt1^tm2Bew/Ckmt1^tm2Bew	involves: 129P2/OlaHsd * C57BL/6	MGI:3693851

Genotype
MGI:2663248

hm1

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

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

behavior/neurological

behavior/neurological phenotype ( J:116302 )

N • both male and female homozygotes display normal home cage locomotion relative to wild-type mice

decreased exploration in new environment ( J:116302 )

• adult male homozygotes (3-5 months of age), exhibit a less active explorative behavior (reduced habituation) over a 30-min period in the open field, as shown by reduced rearing and more sitting relative to wild-type males; however, walking, wall learning, and total walking distance are not significantly different

• unlike wild-type males, ~50% of male homozygotes fail to create a home base during the 30-min open field task, suggesting a tendency for reduced habituation (statistically insignificant)

abnormal spatial learning ( J:116302 )

• adult male homozygotes display slower spatial learning acquisition i.e. significantly higher latencies to find a submerged platform in the water maze test relative to wild-type, caused by a different searching strategy with increased floating in some cases

• notably, male homozygotes show no differences in rotatod performance or during visible platform trials relative to wild-type males, suggesting normal visual and motor function

decreased grooming behavior ( J:116302 )

• although adult wild-type and homozygous mutant mice exhibit a similar reduction in walking over time in the open field test, homozygotes spend significantly less time grooming during a 30-min period relative to wild-type males

decreased startle reflex ( J:116302 )

• although homozygotes show no habituation to the 120 dB startle pulses, they do exhibit a significantly reduced acoustic startle reflex response (only 2-fold the basal activity amplitude) relative to wild-type males (10-fold the basal activity amplitude)

decreased vertical activity ( J:116302 )

• adult male homozygotes exhibit less rearing over a 30-min period in the open field relative to wild-type males

hearing/vestibular/ear

abnormal hearing physiology ( J:116302 )

• similar to wild-type mice, homozygotes display increasing startle amplitudes upon increasing sound levels; however, their response amplitudes only start to rise after receiving stimuli >120-130 dB, indicating higher thresholds of the startle response

nervous system

abnormal prepulse inhibition ( J:116302 )

• unlike wild-type mice, which show a clearcut prepulse inhibition of the startle response (up to 55%) following a prepulse of +16 dB above background, homozygotes fail to exhibit prepulse inhibition of their startle response

digestive/alimentary system

increased defecation amount ( J:116302 )

• adult male homozygotes produce a higher number of feces droppings per 30-min period in the open field relative to wild-type males

growth/size/body

growth/size/body region phenotype ( J:116302 )

N • both male and female homozygotes have a normal life expectancy of ~2 years and show normal development and weight gain, with no differences in average body weight at 3 months relative to age- and sex-matched wild-type mice

reproductive system

reproductive system phenotype ( J:27221 , J:116302 )

N • initial studies indicated that homozygotes are fertile, with no significant differences in sperm motility or ability to produce normal numbers of offspring relative to wild-type mice (J:27221)

N • both male and female homozygotes exhibit normal breeding (J:116302)

homeostasis/metabolism

homeostasis/metabolism phenotype ( J:116302 )

N • homozygotes exhibit normal individual body temperature

integument

integument phenotype ( J:116302 )

N • both male and female homozygotes have a normal fur appearance

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