Phenotypes associated with this allele

• Allele Symbol: Grid2^ho-Nancy
• Allele Name: hotfoot Nancy
• Allele ID: MGI:2655335
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Grid2^ho-Nancy/Grid2^ho-Nancy	involves: C57BL/6	MGI:2655338
ht2	Grid2^Lc/Grid2^ho-Nancy	involves: C57BL/6 * STOCK Mitf^Mi-wh	MGI:2655345

Genotype
MGI:2655338

hm1

• Allelic Composition: Grid2^ho-Nancy/Grid2^ho-Nancy
• Genetic Background: involves: C57BL/6

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

behavior/neurological

impaired balance ( J:82371 , J:82709 )

• in non-rotating rod test, equilibrium times of mutants are lower than controls in all three trials (J:82371)

• mutants fall often, generally after rearing up or grooming, during the period of hyperactivity in response to stimulus (J:82709)

impaired coordination ( J:82371 )

• mutants exhibit poor performance in a motor training test with a rotarod, however they are able to improve their performance over time

abnormal posture ( J:82709 )

• body is flattened to the ground while walking

abnormal locomotor coordination ( J:82371 )

• tapping of the hindpaws; phenotype is much more severe than in Grid2^ho-4J mice

• mutants exhibit increased stumbling frequency in a motor coordination test

ataxia ( J:82371 )

abnormal gait ( J:82709 )

• jumpy, hopping gait; hindlimbs are alternately raised very rapidly

• the angle of the feet is more open in mutants than controls

short stride length ( J:82709 )

• mutants exhibit a reduction in the length of stride by at least half due to mutants moving the same hind foot forward very rapidly, several times in succession, by a very small distance each time, advancing the contralateral foot

retropulsion ( J:82709 )

• adults often walk backwards

abnormal sensory capabilities/reflexes/nociception ( J:82709 )

• upon pressure on the tail, mutants back up or turn around and vocalize instead of running away as do controls

• when flanks are pressed, mutants leap forward powerfully

limb grasping ( J:82709 )

• some mice when lifted by the tail, pull their hind feet together up to the belly

nervous system

abnormal Purkinje cell morphology ( J:82371 , J:82709 )

• Purkinje cells have ectopic spines devoid of presynaptic innervations (J:82371)

abnormal Purkinje cell dendrite morphology ( J:82371 , J:82709 )

• ectopic spines are frequently innervated by parallel fiber varicosities (J:82371)

• occurrence of long ectopic and sometimes branching spines emanating from the proximal dendritic compartment of Purkinje cells (J:82371)

• presence of non-innervated (naked) spines in the vicinity of Purkinje cell dendrites (J:82371)

abnormal cerebellar granule layer morphology ( J:82371 , J:82709 )

• occasional occurrence of pyknotic nuclei in the granule cell layer (J:82371)

• slight atrophy of the granule layer (J:82709)

abnormal cerebellar molecular layer ( J:82709 )

• slight atrophy of the molecular layer

• the molecular layer exhibits atypical axon terminals, with hypertrophy of the smooth endoplasmic reticulum

small cerebellum ( J:82709 )

• cerebellum is slightly reduced in size

cerebellum atrophy ( J:82709 )

• slight atrophy of the granule and molecular layers

abnormal Purkinje cell innervation ( J:82371 )

• although most Purkinje cells are innervated by a single climbing fiber, about 19-20% of cells show innervation by more than one climbing fiber

abnormal CNS synapse formation ( J:82371 , J:82709 )

• mismatching between the length of the presynaptic active zones, in parallel fiber varicosities, and the postsynaptic differentiations in Purkinje cell dendritic spines (J:82371)

• some somatodendritic synapses occur between the perikarya of basket or stellate cells and Purkinje cell dendritic spines or small dendritic profiles (J:82371)

Genotype
MGI:2655345

ht2

• Allelic Composition: Grid2^Lc/Grid2^ho-Nancy
• Genetic Background: involves: C57BL/6 * STOCK Mitf^Mi-wh

behavior/neurological

ataxia ( J:82240 )

nervous system

abnormal cerebellum development ( J:82240 )

• the P0 cerebellum is less developed than in the control

reduced cerebellar foliation ( J:82240 )

• decreased foliation at P5

thin external granule cell layer ( J:82240 )

• external granule cell layer are almost completely absent at P10 and thickness is reduced at P5

abnormal Purkinje cell morphology ( J:82240 )

• depolarization of Purkinje cells is detected at P9 but not earlier; holding currents are significantly larger at P9-P12

• autophagy is detected in P5 Purkinje cells

Purkinje cell degeneration ( J:82240 )

• Purkinje cell degeneration by P5 that is not correlated with depolarization in the cerebellum (first observed at P9)

abnormal cerebellar granule layer morphology ( J:82240 )

• internal granule cell layer is almost completely absent at P10 and thickness is reduced at P5

cerebellum atrophy ( J:82240 )

• cerebellum is atrophic at P21

cellular

abnormal autophagy ( J:82240 )

• autophagy is detected in P5 Purkinje cells

homeostasis/metabolism

abnormal autophagy ( J:82240 )

• autophagy is detected in P5 Purkinje cells