Mouse Genome Informatics
ht
    Ehmt1tm1Yshk/Ehmt1+
involves: C57BL/6J * C57BL/6NCrlj * CBA/JNCrlj
Key:
phenotype observed in females WTSI Wellcome Trust Sanger Institute
phenotype observed in males EuPh Europhenome
N normal phenotype
       
behavior/neurological
• spend less time rearing in the light compartment and make fewer crosses between the light and dark compartments in the light-dark box and in the smaller light-dark box II
• in the smaller light-dark box II mice spend less time in the light compartment
• in a mirrored chamber mice visit the rear less frequently, display a longer latency for first entry, defecate more frequently, and rear less frequently
• bury fewer marbles in a marble burying test
• spend less time walking, rearing, or wall leaning and more time sitting in a new environment
• spend less time rearing in the light compartment and make fewer crosses between the light and dark compartments in a light-dark box
• show reduced exploration in a T maze
• spend less time approaching and sniffing at novel objects (J:157021)
• in the novel object recognition test, heterozygotes do not show any preference for the new object compared with the familiar object after 10 and 80 minute differential intertrial intervals, however at 40 minute differential intertrial interval, they spend a similar amount of time exploring the new object as wild-type mice (J:192316)
• heterozygotes show impaired fear conditioning extinction with an increased sensitivity to external stimuli
• however, spatial learning and memory in the Barnes maze is similar to wild-type mice, even after repetitive training trials
• during the context phase, 24 hours after acquisition, mutants learn the association between the context and aversive stimulus, however they still show twice as much freezing as wild-type mice
• heterozygotes continue to show high freezing levels despite extinction training to tone, which does not decrease significantly over time as in wild-type mice
• heterozygotes exhibit twice as much freezing after a footshock during the acquisition phase
• in the tone test, pre-tone freezing is higher in heterozygotes, however during tone presentations, no differences are seen
• in the spatial object recognition test, heterozygotes do not spend more time exploring an object in the changed position after a 60 minute differential intertrial as do wild-type mice and show no discrimination of the displaced object
• spend less time rearing, or wall leaning and more time sitting in a new environment
• spend less time rearing in the light compartment of a dark-light box, i a mirrored chamber and in a T maze
• spend less time walking and more time sitting in a new environment
• show reduced activity in a T maze
• heterozygotes exhibit increased freezing levels during acquisition and context testing, however the context test freezing levels are comparable with their respective acquisition freezing levels indicating that most likely, mutants show increased sensitivity to sensory stimuli
• heterozygotes show 60% increase in startle responses for 110, 120 and 130 dB pulses compared with wild-type
• auditory brainstem response indicates that hearing is normal
• in a social play test male mice spend less time socially exploring, pouncing and following another mouse
• in a sociability test mice demonstrate a preference for the stranger during the 5-10 min period in contrast wild-type mice no longer show a preference during this time period indicating a prolonged sociability response
• in a social play test male mice spend less time socially exploring
• display a delayed or absent preference for social novelty in a 2 stranger test

nervous system
• hippocampal CA1 pyramidal neurons show a reduced total length, reduced number of branch parts, reduction in the highest branch order, reduced number of endings and smaller total surface area of the apical dendrite, indicating reduced dendritic arborization
• hippocampal neurons show reduced dendritic arborization and decreased spine density
• hippocampal CA1 neurons from secondary and tertiary branches of the apical dendrite show a 15% reduction in the spine density, in particular the stubby and mushroom type spines
• heterozygotes show altered short-term plasticity as indicated by increased paired-pulse facilitation and reduced mEPSC frequency
• however, basal synaptic transmission is normal and no changes in LTP are seen in the hippocampus
• hippocampal neurons show a decrease in the frequency of miniature excitatory postsynaptic currents (mEPSCs) in the presence of tetrodotoxin, picrotoxin and AP-5, however the amplitude is not affected
• hippocampal neurons show increased paired-pulse facilitation

Mouse Models of Human Disease
OMIM IDRef(s)
Kleefstra Syndrome 610253 J:157021 , J:192316