ScaIm1 mutant mice carry a targeted knockout of the Atxn1 gene. Homozygotes appear normal and do not display ataxia.
Huda Zoghbi, Baylor College of Medicine
ScaIm1 mutant mice carry a targeted knockout of the Atxn1 (ataxin 1) gene, as determined by western blot. Homozygotes are viable, fertile, and display a normal life span. Animals have a normal gait without evidence of ataxia up to 30 months of age. Brain weights are similar to control mice, and they show no differences in cell number or neurodegeneration in the cerebellum, brainstem, spinocerebellar tracts, or hippocampus.
Homozygous knockout mice show decreased exploratory behavior in open field tests, however. This reduction does not appear to be due to anxiety, as determined in elevated plus maze tests. Performance in the spatial version of the Morris water maze test is severely impaired, indicative of spatial learning deficits, as visual and motor impairment have not been found.
Exon 8, containing the majority of the coding region (amino acids 1-616), was replaced with a phosphoglyceratekinase hypoxanthine phosphoribosyl transferase (PGK-hprt) expression cassette via homologous recombination in 129S7/SvEvBrd-derived AB2.1 embryonic stem (ES) cells. Resultant chimeric mice were backcrossed to C57BL/6J for more than 10 generations by the donating lab.
|Allele Name||targeted mutation 2, Huda Y Zoghbi|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Atxn1tm1Zuk; Sca1-; Sca1m1|
|Gene Symbol and Name||Atxn1, ataxin 1|
|Strain of Origin||129S7/SvEvBrd-Hprtb-m2|
|Molecular Note||Exon 8 was replaced with a PGK-hprt cassette via homologous recombination resulting in the deletion of amino acids 1-616. Western blot analysis of brain extracts from homozygous mutant animals using an antibody directed against the C-terminus of the protein did not detect protein expression thus verifying the null allele.|
Heterozygotes and homozygotes are viable and fertile.
When using the ScaIm1 mouse strain in a publication, please cite the originating article(s) and include JAX stock #029025 in your Materials and Methods section.