Cloning and expression of a cDNA for the T-cell-activating protein TAP.
The T-cell-activating protein TAP is a murine phosphatidylinositol-anchored glycoprotein whose expression is controlled by the Ly-6 locus. Previous studies have suggested an important role for this protein in physiological T-cell activation. Using oligonucleotide probes, we have now isolated a cDNA clone whose predicted sequence would encode a protein with an NH2-terminal sequence identical to that of the TAP molecule. Further analysis of the predicted protein sequence revealed a cysteine-rich protein with a hydrophobic domain at the COOH terminus and without N-linked glycosylation sites--all features consistent with our previous analysis of the TAP protein. In Southern blot analysis, the Ly-6.2 cDNA clone detects a multigene family and a restriction fragment length polymorphism that maps precisely to the Ly-6 locus. Expression of the cDNA clone in COS cells demonstrates that it codes for TAP and clarifies the relationship between the epitopes recognized by various alpha Ly-6 monoclonal antibodies. Finally, we have studied the expression of Ly-6 mRNA in a variety of cell lineages. Ly-6 transcripts were detected in all organs examined, including spleen, kidney, lung, brain, and heart. This demonstrates that the Ly-6 locus is transcriptionally active in a wide range of organs and suggests that the role of TAP or TAP-like proteins might extend to other tissues.
D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D011061:Poly A / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012689:Sequence Homology, Nucleic Acid; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000954:Antigens, Surface; D012333:RNA, Messenger; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D011061:Poly A; D004247:DNA