B6C3Fe a/a-Wnt1^sw/J

Stock number: 000243
Research areas: Developmental Biology Research, Neurobiology Research

Detailed description

Mice homozygous for the swaying spontaneous mutation (Wnt1^sw) sway to one side or the other when attempting to move and may then pivot clockwise or counterclockwise around their rear legs. Homozygous mutant mice display marked ataxia and hypertonia that is probably attributable to malformations of the anterior vermis of the cerebellum and of the colliculi. The cerebellum is divided on the midline by a deep dorsal sagittal fissure extending from the leptomeninges down to the level of the fourth ventricle. The probable cause is failure of the midline fusion of the cerebellum.

Development

The mutation swaying (Wnt1^sw) arose spontaneously in a cross between mahoganoid (Mgrn1^md), which arose in C3H/HeJ, and downless Jackson (Edar^dl-J), which arose in a cross of two silver stocks at the Jackson Laboratory in 1966. It was sibling mated for 2 generations then a homozygous swaying female was crossed to a C57BL/6J male. The swaying mutation was backcrossed to C57BL/6J for 5 more generations either by mating a progeny tested heterozygous (sw) male or female to a C57BL/6J or by ovary transplant. In 1971 a C57BL/6J velvet coat (Ve) male at N13 was crossed to a host carrying a C57BL/6J sw/sw ovary. The pairs, Ve +/+ sw, were mated at N7 and the stock was maintained in this manner to N7F10. Because of poor breeding a cross to C3HeB/FeJ-a/a was made with a sw/sw ovary transplant. The stock was then maintained by the cross-intercross method using a homozyogus ovary transplant host crossed with a B6C3Fe-a/a F1 male. The stock was frozen in 1982 by mating heterozygous males to heterozygous females at N13. It was thawed and re-frozen in 1990 by intercrossing heterozygotes and again in 2003 by IVF using homozygous sperm and +/? females at [F3NE16p]+F2.

Allele

Symbol: a
Name: nonagouti
MGI accession ID: MGI:1855937
Generation method: Spontaneous
Marker symbol: a
Marker name: nonagouti
Chromosome: 2
Strain of origin: old mutant of the mouse fancy
Molecular note: Characterization of this allele shows an insertion of DNA comprised of a 5.5kb virus-like element, VL30, into the first intron of the agouti gene. The VL30 element itself contains an additional 5.5 kb sequence, flanked by 526 bp of direct repeats (beta4 retroviral sequence). The host integration site is the same as for a^t-2Gso and A^w-38J and includes a duplication of four nucleotides of host DNA and a deletion of 2 bp from the end of each repeat. Northern analysis of mRNA from skin of homozygotes shows a smaller agouti message and levels 8 fold lower than found in wild-type.
General note: Insertion of the LV30 retrotransposon without the beta4 retrovirus sequence does not cause the nonagouti phenotype. J:278039

Allele

Symbol: Wnt1^sw
Name: swaying
MGI accession ID: MGI:1856382
Generation method: Spontaneous
Marker symbol: Wnt1
Marker name: wingless-type MMTV integration site family, member 1
Chromosome: 15
Strain of origin: STOCK Atrn^mg Edar^dl-J
Molecular note: The mutation is a deletion of 1 guanosine residue from a run of 4 consecutive guanosines beginning at genomic nucleotide 1888. This mutation is predicted to cause a frameshift mutation resulting in a stop codon 10 codons downstream from the deletion. The predicted protein would lack critical amino acids for biological activity.