Abstract |
Deficient expression of glycoinositol phospholipid ( GPI) anchored proteins in affected paroxysmal nocturnal hemoglobinuria (PNH) cells has been traced to a defect in GPI anchor assembly. In a previous study (Schubert, J., Schmidt, R. E., and Medof, M. E. (1993) J. Biol. Chem., in press) we characterized the biosynthesis of putative Man-containing GPI anchor precursors in normal peripheral blood lymphocytes and investigated assembly of these intracellular GPI intermediates in CD48- affected and CD48+ unaffected T and natural killer cell lines of PNH patients. We found that affected T cells from five patients exhibited a uniform defect in which dolichol-phosphoryl-Man was synthesized but no GPI mannolipids were expressed. In this study, membranes of patients' affected T cells were labeled with UDP-[3H]GlcNAc to evaluate earlier steps in GPI synthesis, and intact cells were fused to Thy-1- murine lymphoma mutants harboring different defects in early GPI assembly to test for the presence of corresponding or complementary lesions. In all cases, affected cell membranes failed to assemble GlcNAc- inositol phospholipid, the initial precursor of GPI anchor structures, and the intact cells failed to complement class A mutants while complementing other classes. Affected polymorphonuclear leukocytes from three additional patients of different origin were then labeled with [3H]Man and the labeling patterns found to correspond to those obtained with the T lymphocytes. Taken together the data indicate that the genetic lesion in PNH cells resides in a DNA element which: 1) encodes a product required for the synthesis of GlcNAc- inositol phospholipid, 2) corresponds to that altered in class A Thy-1- murine lymphoma mutants, and 3) is commonly affected in different patients.
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Authors | C Armstrong, J Schubert, E Ueda, J J Knez, D Gelperin, S Hirose, R Silber, S Hollan, R E Schmidt, M E Medof |
Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 267
Issue 35
Pg. 25347-51
(Dec 15 1992)
ISSN: 0021-9258 [Print] United States |
PMID | 1460030
(Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Antigens, CD
- CD48 Antigen
- CD48 protein, human
- Cd48 protein, mouse
- Glycosylphosphatidylinositols
- Uridine Diphosphate N-Acetylglucosamine
- Dolichol Monophosphate Mannose
- Mannose
- Acetylglucosamine
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Topics |
- Acetylglucosamine
(metabolism)
- Animals
- Antigens, CD
(genetics)
- CD48 Antigen
- Cell Membrane
(metabolism)
- Dolichol Monophosphate Mannose
(metabolism)
- Glycosylphosphatidylinositols
(metabolism)
- Hemoglobinuria, Paroxysmal
(genetics, immunology, metabolism)
- Humans
- Killer Cells, Natural
(immunology)
- Lymphoma
(genetics, immunology, metabolism)
- Mannose
(blood)
- Mice
- Mutation
- Neutrophils
(immunology, metabolism)
- Trypanosoma brucei brucei
(metabolism)
- Uridine Diphosphate N-Acetylglucosamine
(metabolism)
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