Mice homozygous for the Cntn1m1J mutation are smaller than their wild-type littermates by 4 to 7 days of age, and appear emaciated by 2 weeks of age. They are ataxic, most die by 18 to 20 days of age, and all die by 30 days of age. Histological assessment found normal neuromuscular junctions, normal Purkinje cell dendritic arborization, and no morphological anomalies in brain. The twitch and titanic force generated by excised extensor digitorum longus muscles was found to be normal when normalized for the muscle weight of these smaller mutants. Necropsies showed pale livers, little food in the stomachs, and gas bubbles in the intestines.
The Cntn1m1J mutation arose spontaneously at The Jackson Laboratory on the BALB/cJ inbred in 1979. It was maintained by sibling inbreeding for several generations then it was maintained by breeding the host of a homozygous ovarian transplant to a BALB/cByJ male and intercrossing the obligate heterozygous offspring. This backcross-intercross breeding scheme was maintained for many years, reaching generation N4 in 1985, N10 in 1987, N17 in 1993, and N19 in 1993. In 1999 embryos were generated for cryopreservation from C57BL/6J females bred with heterozygous males at generation N21. When these embryos were later cryorecovered they were intercrossed and then the line was backcrossed once to BALB/cByJ before being maintained by breeding a host of a homozygous ovarian transplant with a male sibling of the donor then intercrossing the obligate heterozygotes. In 2011 this strain reached generation N1F19. Prior to cryopreservation a DNA sample of the BALB/cByJ background at generation N21 was preserved in the DNA Resource and is available as stock No.017747.
|Allele Name||mutation 1, Jackson|
|Gene Symbol and Name||Cntn1, contactin 1|
|Strain of Origin||BALB/cJ|
|Molecular Note||A spontaneous G-to-A point mutation at 92,250,964 of Chr15 (GRCm38) changes tryptophan codon 364 into a premature stop codon at position 364 (p.W364*). Western blot of brain or spinal cord extracts from homozygotes failed to identify this protein and efforts to amplify segments of this gene from cDNA failed.|
When using the B6;C-Cntn1m1J/GrsrJ mouse strain in a publication, please cite the originating article(s) and include JAX stock #002717 in your Materials and Methods section.