Disease relevance of B4GALNT2

• In conclusion, a segment of the cDNA for betal,4GalNAcT which determines expression of the Sda carbohydrate structure was obtained, and reduced transcription of this beta 1,4GalNAcT resulted in the disappearance of the Sda epitope in gastrointestinal cancer [1].
• Expression of UDP-GalNAc:NeuAc alpha 2,3Gal beta-R beta 1,4(GalNAc to Gal) N-acetylgalactosaminyltransferase involved in the synthesis of Sda antigen in human large intestine and colorectal carcinomas [2].
• Treatment of the Cad ganglioside with Arthrobacter ureafaciens neuraminidase yielded a product reactive with monoclonal antibody 2D4, which is specific for terminal GalNAc beta (1-4)Gal structures [3].
• Cad gene activities are induced in MCF-7 human breast cancer cells, and treatment of MCF-7 or ZR-75 cells with 10 nM 17beta-estradiol (E2) resulted in a 3- to 5-fold increase in cad mRNA levels in both cell lines [4].
• The hypothesis that the infection by pyelonephritogenic Escherichia coli strains with specific adhesins for the alpha 2,3sialyl-galactosyl structure might operate as selective agents for the high frequency of Sda antigen in distal renal cells is discussed [5].

Psychiatry related information on B4GALNT2

• Enzymatic characterization of the protein expressed by this cDNA demonstrates that it encodes a beta 1,4-N-acetylgalactosamine transferase activity that can add to the low molecular weight acceptor 3'-sialyl-N-acetyllactosamine, to form the nonreducing terminal tetrasaccharide Sda blood group structure [6].

High impact information on B4GALNT2

• We found that the majority of the O-glycans that are linked to mZP3 are core type 2 sequences terminated with sialic acid, lacNAc (Galbeta1-4GlcNAc), lacdiNAc (Gal-NAcbeta1-4GlcNAc), Galalpha1-3Gal, and NeuAcalpha2-3[GalNAcbeta1-4]Galbeta1-4 (Sda antigen) [7].
• The Cad-active glycoprotein antigens in cultured human hepatocellular carcinoma cells appeared as triplet bands having molecular weights of 92,000, 75,000, and 61,000, under either reducing or nonreducing conditions in sodium dodecyl sulfate-polyacrylamide gel electrophoresis [8].
• By using these monoclonal antibodies, it was revealed that many cultured human hepatocellular carcinoma cell lines and cancer tissues taken from patients with hepatocellular carcinoma contain both Cad-active glycoprotein antigens and related gangliosides, while normal liver tissues contain no appreciable amount of either species of antigen [8].
• N-Acetylgalactosamine beta 1,4-linked to a galactose residue substituted in O-3 with one N-acetylneuraminic acid residue is the immunodominant sugar of the human blood group Sda antigen which is also largely present in the kidney medulla and colon mucosa [2].
• Moreover, a comparative study of the Sda/Cad and ABH blood group determinants along the gastrointestinal tract showed the same reverse distribution in the two kinds of antigens [9].

Biological context of B4GALNT2

• Upon transient transfection in Cos-7 cells of the common catalytic domain, a soluble form of the protein was obtained, which catalysed the transfer of GalNAc residues to alpha2,3-sialylated acceptor substrates, to form the GalNAcbeta1-4[Neu5Acalpha2-3]Galbeta1-R trisaccharide common to both Sd(a) and Cad antigens [10].
• A crude ganglioside fraction was prepared from Cad cells and found to inhibit the hemagglutination reaction, whereas neutral glycolipids were inactive [11].
• M1T1 Sda shares two highly conserved domains with several DNases and putative DNases in streptococci; however, it possesses a unique C-terminal amino acid sequence [12].
• Structure determination of the major acid components by methylation analysis, g.l.c.-m.s. and 1H-n.m.r. indicated that the three blood group Cad red cells under study (samples Cad., Bui. and Des.) carry the same pentasaccharide GalNAc(beta 1-4)[NeuAc(alpha 2-3)]Gal(beta 1-3)[NeuAc(alpha 2-6)]GalNAc -ol(Cad determinant) but in different amounts [13].
• Donor specificity in the glycosylation of Tamm-Horsfall glycoprotein: conservation of the Sda determinant in pairs of twins [14].

Anatomical context of B4GALNT2

• The Sda blood group carbohydrate structure, GalNAcbeta1-4[NeuAcalpha2-3]Galbeta1-4GlcNAc-R, is expressed on glycolipid and glycoprotein in human gastrointestinal mucosa [1].
• From the total RNA fraction of human gastric mucosa, we have amplified a cDNA segment by reverse-transcription-polymerase-chain reaction (RT-PCR), using primers designed according to the cDNA sequence of a murine beta1,4GalNAcT which synthesizes the Sda determinant [1].
• Identification of a novel ganglioside on erythrocytes with blood group Cad specificity [11].
• Glycophorin A and B from Cad erythrocyte membranes are the carriers of the blood group Cad determinants [15].
• The blood group Cad antigen is a carbohydrate structure well characterized on the sialoglycoproteins of the red cell membrane from some rare individuals (Blanchard, D., Cartron, J. P., Fournet, B., Montreuil, J., Van Halbeck, H., and Vliegenthart, J.F.G. (1983) J. Biol. Chem. 258, 7691-7695) [11].

Associations of B4GALNT2 with chemical compounds

• These results together with cell surface labeling experiments suggest that the major ganglioside of Cad erythrocytes might be derived from sialosylparagloboside by substitution with an additional N-acetylgalactosamine residue [11].
• Previous work has shown that the oligosaccharide structure recognized by the CT antibodies is identical, at least in part, to that of the human Sda blood group, a structure formed through enzymatic addition of N-acetylgalactosamine in beta 1,4-linkage to a sub-terminal galactose substituted with an alpha 2,3-linked N-acetylneuraminic acid residue [6].
• From the results presented above and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis studies it is suggested that Cad red cells from Bui. and Des. do not carry a mixture of glycophorin A molecules with or without the Cad pentasaccharides but a spectrum of glycoprotein molecules with varying amounts of Cad determinants [13].
• Profiling of the carbohydrate moieties of Asn208 indicates a large heterogeneity, similar to that established for native human Tamm-Horsfall glycoprotein, namely, multiply charged complex-type carbohydrate structures, terminated by sulfate groups, sialic acid residues, and/or the Sda-determinant [16].
• Differences were observed in the total amount of released tetra- and Sda-active pentasaccharide of the used donors (42, 470, 478, 718 microg/100 mg THp), indicating that the presence of repeating N-acetyllactosamine units incorporated into the N-glycan moiety of THp is donor specific [17].

Other interactions of B4GALNT2

• Molecular cloning, gene organization and expression of the human UDP-GalNAc:Neu5Acalpha2-3Galbeta-R beta1,4-N-acetylgalactosaminyltransferase responsible for the biosynthesis of the blood group Sda/Cad antigen: evidence for an unusual extended cytoplasmic domain [10].

Analytical, diagnostic and therapeutic context of B4GALNT2

• An RT-PCR product of 390 bp shared 85% nucleotide identity with the murine Sda-related beta1,4GalNAcT [1].
• Further analysis of the ganglioside extract from Cad erythrocytes by thin layer chromatography revealed an unusual profile characterized by a lower content of sialosylparagloboside and the presence of a novel ganglioside of slower mobility [11].
• Southern blot analysis of genomic DNA using the Cad cDNA as a hybridization probe gave simple patterns, consistent with our interpretation that pine Cad is a single-copy gene [18].
• In Sda serological tests the product formed with 3'-sialyl-N-acetyllactosamine was highly active whereas that formed with 3'-sialyllactose had only weak activity [19].

References