A^iapy

Southern blot analysis showed that this allele is the result of a 5.2 kb intracisternal A particle (IAP) transposon insertion in an antisense orientation immediately 5' of the first coding exon of the agouti gene. This results in ectopic and differential expression of agouti protein via utilization of a cryptic promoter within the IAP 5' long terminal repeat (LTR) and variable methylation. Methylation assay results indciate that the agouti and yellow mosaic phenotype characteristic of this allele is due to differential epigenetic methylation of the IAP. mRNA from this allele was found to be ectopically over-expressed in several adult tissues from heterozygous mice. The transcript was the same size as mRNA from the wild-type allele. The mutation occurred in a C3H/HeJ A allele. (J:18848, J:21244, J:79708)