In(2a;Itch)18H

This allele comprises a paracentric inversion that affects minimally two loci, agouti and Itch. A deletion of 18 and 20 bp from the proximal and distal breakpoints, respectively, occurred when the inversion was formed. Restriction digests of genomic clones suggests the distal breakpoint is located in intronic sequences between exons 1 (nts 1-98) and 2 (nts 99-189). Exon 2 of Itch was localized to within 600 bp distal to the inversion's distal breakpoint, placing exon 1 within the inverted region and near the proximal breakpoint. Exon trapping technology revealed that the distal breakpoint encompasses a novel E3 ubiqutin protein ligase. Northern analysis showed that this allele is missing a 5.1-kb message sequence when probed with Itch cDNA normally found in wild-type mice; the inversion event appears to have removed the promoter from the coding region of the Itch gene. (J:45910)