Assignment of swine TNFRSF6 (Fas) to chromosome 14q25→q27 and TNFSF6 (FasL) to chromosome 9q14→q22 by FISH and radiation hybrid mapping

Some of the first signals that initiate programmed cell death (apoptosis) are mediated by specific receptors on the cell surface. Fas (also designated as CD95 or APO-1), which is a 45kDa protein that belongs to the tumor necrosis factor (TNF) receptor superfamily and has one transmembrane domain, has been identified as the molecule that transduces the apoptosis induction signal intracellularly (Yonehara et al., 1989; Itoh et al., 1991). Fas ligand (FasL or CD95L) is a 40-kDa protein that belongs to the TNF superfamily. Cells that express FasL interact directly with cells expressing Fas, and FasL acts as an apoptosis inducer through Fas molecules. Expression of the Fas molecule is detected in various organs, with marked expression on activated mature T and B cells and liver cells. FasL is expressed on activated mature T cells, and also in the testis. The Fas and FasL system is one of the major pathways of the induction of apoptosis, and defects of this system result in autoimmune disease, as has been shown by analyses of lpr and gld mice (Watanabe-Fukunaga et al., 1992; Takahashi et al., 1994). Swine Fas and FasL cDNAs were previously cloned, and their function has been intensively analyzed (Muneta et al., 2001). Genetic modification of Fas or FasL in swine will yield clues about the mechanism of autoimmune diseases like SLE, and aid the development of methods for the regulation of rejection of donor organs in xenotransplantation. Here we report the locations of Fas and FasL genes (designated TNFRSF6 and TNFSF6, respectively) on swine chromosomes by FISH analysis. We also confirmed these locations by radiation hybrid mapping.