Mutations in the Fas antigen gene in lpr mice

The Fas antigen is a cell surface protein belonging to the tumor necrosis factor/nerve growth factor receptor family and it mediates apoptosis. The Fas antigen gene is the structural gene for the mouse mutation, lpr (lymphoproliferation). In one allele of lpr, an early transposable element (a mouse endogenous retrovirus) is inserted into an intron of the Fas antigen gene, which causes premature termination and aberrant splicing of the Fas antigen transcript. In the other allele (lprcg), a point mutation in the signal transducing domain of the cytoplasmic region abolishes the function of the Fas antigen.