Atxn1^tm2Zuk

An expanded tract of 78 CAG repeats was engineered and knocked into exon 7 by replacing the PPPQQ codons with 78 glutamine (Q) codons and a loxP site flkanked neomycin resistance gene cassette was inserted into intron 6. Transient expression of Cre recombinase in correctly targeted ES cells removed the neo cassette. Expression of the mutant allele was verified by Western blot analysis of brain protein extracts. The CAG expansion mimics mutations found in human spinocerebellar ataxia type 1 patients with CAG expansions ranging from 40-83 repeats. (J:61398)