title: Mls-1 is encoded by the long terminal repeat open reading frame of the mouse mammary tumor provirus Mtv-7.
abstract: The murine Mls-1 antigen is the prototype of endogenous superantigens, molecules whose activities lead to deletion of T cells expressing certain T-cell receptor V beta genes from the mature repertoire. However, Mls-1 also stimulates T cells expressing these particular V beta genes (V beta 6, V beta 7, V beta 8.1, and V beta 9) in vitro, making it one of the strongest known T-cell activators. We have recently reported that the Mls-1 gene is closely linked to the endogenous mammary tumor virus Mtv-7. We now demonstrate that Mls-1 is encoded by the open reading frame in the U3 region of the long terminal repeat of Mtv-7. However, control of expression of this molecule seems complex, depending on the promoter used for the transfection experiments. The sequence of the Mtv-7 open reading frame differs from all other known mammary tumor virus open reading frame sequences in the 3' end, suggesting that the T-cell receptor V beta specificity is conferred by the C terminus of the molecule. The predicted structure of the protein encoded by the open reading frame is consistent with a type II transmembrane molecule where the C terminus is extracellular.
authors.affiliation: Department of Pathology, Tufts University School of Medicine, Boston, MA 02111.
authors.forename: U
authors.initials: U
authors.lastname: Beutner
authors.forename: W N
authors.initials: WN
authors.lastname: Frankel
authors.forename: M S
authors.initials: MS
authors.lastname: Cote
authors.forename: J M
authors.initials: JM
authors.lastname: Coffin
authors.forename: B T
authors.initials: BT
authors.lastname: Huber
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains; D016747:Minor Lymphocyte Stimulatory Antigens / Q000235:genetics*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016366:Open Reading Frames; D011533:Proviruses / Q000235:genetics*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000276:immunology; D014162:Transfection
chemical_list: D016747:Minor Lymphocyte Stimulatory Antigens; D009838:Oligodeoxyribonucleotides; D011948:Receptors, Antigen, T-Cell