UDP-GlcNAc:Galbeta1-->3GalNAc (GlcNAc to GalNAc) beta1-->6N-acetylglucosaminyltransferase holds a key role on the control of CD15s expression in human pre-B lymphoid cell lines.
Expression mechanism of CD15s (sialyl-Lex, sLex) antigen has been investigated using human B lymphoid cell lines. sLexstructures were not expressed in mature B lymphoids but highly expressed in pre-B leukemia and pre-B lymphoma cell lines. The expression site was mainly on the O -linked oligosaccharide chains and E-selectin mediated-cell adhesion capability of sLex-positive cells were significantly suppressed by benzyl-alpha-GalNAc treatment. Subsequently, the bases of the sLexexpression control mechanism were examined at the levels of enzymatic activities and transcripts of glycosyltransferases. (1) The activities of alpha1-->3fucosyltransferase, alpha2-->3sialyltransferase, beta1-->4Gal-transferase, and elongation beta1-->3GlcNAc-transferase, did not correlate with sLexexpression levels. (2) The transcripts of Fuc-TVII were not parallel with sLexexpression, and those of ST3Gal IV and beta1-->4Gal-transferase were constitutively detected in all cell lines tested. (3) There was no detectable enzyme activity for core 3 and 4 backbone structure synthesis in human B cell lines. (4) By contrast, the enzyme activities and transcripts of UDP-GlcNAc:Galbeta1-->3GalNAc (GlcNAc to GalNAc) beta1-->6 N -acetylglucosaminyltransferase (Core2GnT) had significant correlation with the cell surface expression of sLexantigen. (5) Moreover, Western blot analysis revealed the presence of a major approximately 150 kDa glycoprotein that carries O -linked oligosaccharides recognized by anti-sLexmonoclonal antibody in sLex-positive pre-B leukemia cell lines. This correlation of Core2GnT with CD15s expression suggests that Core2GnT is a regulator of the cell surface expression of sLexin human pre-B lymphoid cells.
Nakamura
M
M
Division of Hemopoiesis and Division of Hemostasis and Thrombosis Research, Institute of Hematology, and Department of Allergy and Collagen Disease, Jichi Medical School, Minamikawachi, Tochigi 329-04, Japan.
Furukawa
Y
Y
Sasaki
R
R
Masuyama
J
J
Kikuchi
J
J
Iwase
S
S
Kudo
T
T
Narimatsu
H
H
Asakura
S
S
Fujiwara
S
S
Inokuchi
J
J
D015703:Antigens, CD; D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002448:Cell Adhesion; D019040:E-Selectin / Q000235:genetics / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis; D051917:Leukosialin; D016256:Lewis X Antigen / Q000032:analysis* / Q000737:chemistry; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000032:analysis; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000201:enzymology / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000032:analysis; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D019040:E-Selectin; D018960:Hyaluronan Receptors; D051917:Leukosialin; D016256:Lewis X Antigen; D009844:Oligosaccharides; C465014:SPN protein, human; D012795:Sialoglycoproteins; D017351:N-Acetylglucosaminyltransferases; C053024:beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase