A new allele, ho15J, of the Grid2 gene

Sandra J. Gray, Susan A. Cook, Kenneth R. Johnson, and Muriel T. Davisson

Source of Support: This research was supported by NIH/NCRR grant RR01183 (M,. T. Davisson, PI) and Cancer Core Grant CA34196.

Mutation (allele) symbol: ho15J

Mutation name: hot foot 15 Jackson

Gene symbol: Grid2

Strain of origin: C3.Cg-scb/J

Current strain name: C3(Cg)-Grid2ho15J/J

Stock# 005344 (Note: as of 7-14-2006 available as DNA only from the DNA Resource at The Jackson Laboratory)

Phenotype Categories: neurological/behavorial: motor capabilities/coordination/movement anomalies

Origin and Description:

The spontaneous ho15J mutation was found by Sandra Gray in the C3.Cg-scb/J colony in the Mouse Mutant Resource at The Jackson Laboratory in May 2002. An outcross with C57BL/6J  produced normal appearing F1 hybrids and yielded 2 mutant mice in a total of 18 raised in three F2 litters; hence, this mutation is inherited as a recessive allele. When walking, homozygous mutants exhibit a slight jolting throughout the length of the body and a wobbly gait. They may slowly raise their rear feet high into the flank while holding their rear feet more rigidly than normal, but they do not exhibit the more common walking- on- hot coals phenotype of other hotfoot mutations. Lateral and vertical head movement is much milder than that presented by lurcher mutants. Homozygous ho15J/ho15J mutants can be classified at three weeks of age. Homozygous females breed very well, but males do not; thus, the colony is maintained by mating homozygous females to heterozygous males. DNA from mutants and controls is available from TJL DNA Resource.

Genetic Analysis:

 An intercross with CAST/Ei generated 40 meioses that mapped this mutation between D6Mit184-D6Mit3. Since Grid2 lies within this flanked region, a homozygous new mutant was mated to a homozygous Grid2 ho4J/Grid2 ho4J male. Twenty affected and no normal progeny were seen in two litters demonstrating that the new mutatiion is an allele of Grid2.

Pathology:

ABR tests showed that ho15J/ho15J mice have normal hearing. Ocular morphology is normal except for the retinal degeneration of the C3H background. Our routine screen of other tissues from mutants at 41 weeks of age showed no lesions.

Acknowledgements:

 We thank Norman Hawes, Coleen Marden, Heping Yu and Rod Bronson for clinical assessments. We thank Melissa Berry and Pat Ward Bailey for assistance with Web posting.