Identification and structural characterization of an LYT-2/3 homolog in tunicates.
1. A serologic and structural homolog to murine Lyt-2/3 molecular complex was sought in tunicate hemocytes by using a monoclonal antibody specific to Lyt-2 framework determinants (mAb 53-6.7). 2. This antibody labeled a distinct population of tunicate hemocytes, as determined in indirect immunofluorescence and FACS analysis, and immunoprecipitated disulfide-bonded subunits from hemocytes equivalent to the 38 kDa (alpha), 34 kDa (alpha') and 30 kDa (beta) subunits of murine Lyt-2/3 molecules. 3. As in mice, tunicate alpha- and alpha' -subunits each appeared to bear three N-linked oligosaccharides, one high mannose- and two complex-type glycans and focused as a number of heterogeneous spots on IEF gels. 4. In contrast, beta-subunits of both species were associated with a single N-linked glycan of the complex type and focused as basic components of limited charge heterogeneity. 5. Based on tryptic peptide patterns, alpha and alpha' -subunits, are likely to be structurally similar in both tunicate and mouse complexes. 6. However, CNBr cleavage patterns indicated that the alpha-subunit of both species may differ in the size-location of the intrachain disulfide bridge. 7. Collectively our observations suggest the phylogenetic emergence of an Lyt-2/3 homolog at an early level of evolution.
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Department of Anatomy and Cell Biology, UCLA School of Medicine, 90024-1763.
Mansour
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Cooper
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D000818:Animals; D000911:Antibodies, Monoclonal; D000950:Antigens, Ly / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D005075:Biological Evolution; D003488:Cyanogen Bromide; D000939:Epitopes / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007518:Isoantibodies / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011134:Polysaccharides / Q000032:analysis; D012995:Solubility; D014561:Urochordata / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D000939:Epitopes; D007518:Isoantibodies; C029805:Lyt antibodies; D011134:Polysaccharides; D003488:Cyanogen Bromide