AIM-1 Transgenic mice with a curly tail phenotype and its chromosome location

In normal mouse colonies, curly tail mice arise due to spontaneous mutations. This phenotype closely resembles human neural tube defects (Korf, 1996). Genetically, the curly tail phenotype is determined by a single Mendelian locus, called ct (Van Straaten and Copp, 2001). Positional cloning indicated that the gene for curly tail is located on chromosome 4. Apart from this ct gene, there are certain modifier genes also involved in this phenotype in mice (Neuman et al., 1994). We created transgenic mouse lines with rat AIM-1 cDNA (Ying et al., 2000) driven by a specific promoter. Out of eight founder lines, one had a curly tail phenotype. This line did not express the transgene. Fluorescence in situ hybridization (FISH) indicated that the transgene was inserted into a gene on chromosome 10, which disturbed gene expression involved in tail development. Interestingly, Donforth's short tail gene is also on chromosome 10 (Alfred et al., 1997), but it is away from this region of integration.