Biochemical characterization of murine lymphoid alloantigen Ly-m20.2, a cell surface marker controlled by a gene linked to the Mls locus.
The lymphoid alloantigen Ly-m20.2 is expressed on the majority of B cells and a wide variety of hemopoietic cells including stem cells. However, it is not detectable on T lymphocytes. Genetic studies indicate that expression of Ly-m20.2 is controlled by a gene(s) closely linked to the M1s locus. Our present biochemical analysis shows that Ly-m20.2 is a monomeric glycoprotein of 55,000 to 60,000 daltons, with no detectable intramolecular disulfide bonds. The Ly-m20.2 molecules of tissues and clonal cell lines exhibit size and charge heterogeneity that can be eliminated by the complete removal of N-linked sugars with the enzyme endo-F or by inhibiting glycosylation with tunicamycin. The resulting unglycosylated Ly-m20.2 molecule migrates as a single band of 40,000 daltons in SDS-gels and behaves as a single charge species in IEF. The Ly-m20.2 antigen was compared biochemically with two other alloantigens: LyM-1, an alloantigen whose expression is also controlled by gene(s) tightly linked to the M1s locus, and Ly-17.1, an alloantigen serologically allelic to the Ly-m20.2 antigen. Immunoprecipitates obtained with the respective LyM-1 and Ly-17.1 antisera yielded similar 55,000 to 60,000 dalton molecules from cells of the appropriate mouse strains. In the case of LyM-1, sequential immunoprecipitation provided evidence that Ly-m20.2 and LyM-1 are identical.
Mark
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Kimura
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Hämmerling
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D000818:Animals; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D000950:Antigens, Ly / Q000032:analysis* / Q000235:genetics; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005796:Genes; D008040:Genetic Linkage; D007519:Isoantigens / Q000032:analysis* / Q000235:genetics; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL
D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D007519:Isoantigens