Mice heterozygous for the trembler-Jackson spontaneous mutation (Pmp22Tr-J) are similar to heterozygotes carrying the original trembler mutation (Pmp22Tr). However, the behavior and neuropathology of trembler-Jackson heterozygotes is less severe. The tremor phenotype cannot be reliably recognized before 20 to 25 days. There are no obvious seizures and only a mild gait abnormality. In the PNS, the myelin deficiency is considerably less severe than that of trembler mice. Homozygous trembler-Jackson mice are recognizable by 8 days of age after which they become progressively disabled. Homozygous mutant mice are unable to walk normally and can right themselves only with great difficulty; most are dead by 18 days. It should be noted that although trembler homozygotes are more severely demyelinated than trembler-Jackson homozygotes, the trembler mice live a normal lifespan while trembler-Jackson mice die prior to weaning. Survival of trembler homozygotes suggests that peripheral myelin is not essential for survival. The PNS is nearly devoid of myelin with myelinogenesis blocked in the promyelin stage. Schwann cells ensheathe individual axons but without formation of compact myelin.
The trembler Jackson mutation arose spontaneously in the DBA/2J inbred strain at The Jackson Laboratory in 1967. This dominant mutation was maintained in the laboratory of Dr. Eva Eicher by backcrossing to C57BL/6J and C57BL/6JEi, reaching N14 in 1976, and N19F4 in 1978. This congenic strain was passed to the Mouse Mutant Resource, where it was maintained by backcrossing to C57BL/6J for many years then maintained by sibling intercrossing, and in 2007 sperm was cryopreserved from heterozygous males at generation N41F22.
|Allele Name||trembler Jackson|
|Allele Synonym(s)||TrJ; trembler-j; TrJ|
|Gene Symbol and Name||Pmp22, peripheral myelin protein 22|
|Strain of Origin||C57BL/6J|
|Molecular Note||Sequence analysis of cDNA showed a T-to-C transition at coding nucleotide 47 resulting in the substitution of a leucine residue by a proline residue at position 16 (p.L16P).|
When using the trembler Jackson mouse strain in a publication, please cite the originating article(s) and include JAX stock #002504 in your Materials and Methods section.