Mouse strains with point mutations in TAP1 and TAP2

Abstract

We report two new mouse strains: Jasmine (C57BL/6J/Apb-Tap2jas/Apb), with a point mutation in the transporter associated with antigen processing (TAP)2; and Rose, (C57BL/6J/Apb-Tap1rose/Apb), with a point mutation in TAP1. These strains were detected as the result of ethyl nitroso urea (ENU) screens for recessive point mutations affecting the immune system. As expected in cases of defective TAP expression, the mice have very low major histocompatibility complex (MHC)-I cell-surface expression, and few CD8+ T cells. The Rose strain has an A to T substitution in exon 10 of TAP1, resulting in an asparagine to valine substitution at position 643. Jasmine has an A to C transversion in exon 5 of TAP2, resulting in a threonine to proline substitution at position 293 of the protein. The mutation does not affect mRNA levels, but results in a very severe reduction in TAP2 protein. TAP1 protein levels are also decreased in Jasmine mice, demonstrating a new role for mouse TAP2 in stabilizing TAP1 protein expression. Jasmine is the first strain available with defective TAP2. The two mouse strains provide additional animal models for the human condition Bare Lymphocyte syndrome type 1, and identify new residues important for TAP function.