Phenotypes associated with this allele

• Allele Symbol: Grin2b^tm1Mim
• Allele Name: targeted mutation 1, Masayoshi Mishina
• Allele ID: MGI:1928295
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Grin2b^tm1Mim/Grin2b^tm1Mim	involves: C57BL/6 * CBA	MGI:4360658
ht2	Grin2b^tm1Mim/Grin2b^+	B6.Cg-Grin2b^tm1Mim	MGI:4943914

Genotype
MGI:4360658

hm1

• Allelic Composition: Grin2b^tm1Mim/Grin2b^tm1Mim
• Genetic Background: involves: C57BL/6 * CBA

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

mortality/aging

neonatal lethality, complete penetrance ( J:31622 )

• mice die shortly after birth without feeding; these mice can survive as long as P6 if hand-fed

behavior/neurological

absent gastric milk in neonates ( J:31622 )

• unless hand-fed, mice do not have milk in stomachs up to 6-7 hours after birth

absent suckling reflex ( J:31622 )

• sensory inputs do not induce the suckling response in mutant neonates

nervous system

disorganized barrel cortex ( J:31622 )

• no clear barrelettes are seen at P0 and at P2

• the terminal arbors of the primary sensory neurons in the barrelette regions have a diffuse distribution pattern and no distinct clustering is seen, whereas in control mice, terminal clusters coincide with barellettes

abnormal AMPA-mediated synaptic currents ( J:178913 )

• significant increase in mean mEPSC amplitudes

absence of NMDA-mediated synaptic currents ( J:31622 )

• in hippocampal CA1 slices, no NMDA component of EPSPs is detectable in mutant mice

absent long-term depression ( J:31622 )

• in hippocampal slices, no long lasting depression is observed in P2-P3 mutant mice

Genotype
MGI:4943914

ht2

• Allelic Composition: Grin2b^tm1Mim/Grin2b⁺
• Genetic Background: B6.Cg-Grin2b^tm1Mim

behavior/neurological

increased startle reflex ( J:89405 )

• enhanced startle response when presented with 60 startle stimuli of 120-dB bursts of sound for 50 ms over the 30-min test

• enhanced startle response at sound levels of 90 - 120 dB

• however, no differences in ABR thresholds are detected compared to wild-type mice

nervous system

increased prepulse inhibition ( J:89405 )

• slightly increased