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PubMed1984

Oligosaccharide composition of calf rotavirus.

The oligosaccharides of the structural glycoprotein (VP7) of calf rotavirus were characterized. The precursor of VP7 produced in infected cells in the presence of tunicamycin migrated on SDS-polyacrylamide gels with an apparent molecular weight 6000 less than the glycosylated glycoprotein. Endoglycosidase (Endo) H digestion of the mature virus resulted in a decrease of 5000 in the molecular weight of VP7 in two discrete stages. Analysis of Endo H-treated, 3H-labelled digestion products of VP7 on Bio-Gel P-4 identified an oligosaccharide of molecular weight 1350 as the predominant form. Further treatment of the digest with mannosidase and analysis on Bio-Gel P-2 columns indicated that the oligosaccharide was digested into a free mannose and an oligosaccharide of molecular weight 400 in the ratio of 6:1. This indicates that the oligosaccharides of VP7 consist of four N-linked (Man)7 residues, two of which occupy more exposed and two more cryptic positions in the VP7 molecule.

Animals↗
PubMed2004

Significance of the oligosaccharides of the porcine reproductive and respiratory syndrome virus glycoproteins GP2a and GP5 for infectious virus production.

The arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) contains four glycoproteins, GP(2a), GP(3), GP(4) and GP(5), the functions of which are still largely unresolved. In this study, the significance of the N-glycosylation of the GP(2a) and GP(5) proteins of PRRSV strain LV was investigated. Both glycoproteins contain two predicted N-glycosylation sites that are highly conserved between North American-type and European-type PRRSV. Using site-directed mutagenesis, single and double mutant full-length PRRSV cDNA clones were generated. After analysing the expression of the mutant proteins and the actual use of the four putative glycosylation sites in the wild-type proteins, the production of mutant virus particles and their infectivities were investigated. The results showed that the N-linked glycans normally present on the GP(2a) protein are not essential for particle formation, as is the oligosaccharide attached to N53 of the GP(5) protein. In contrast, the oligosaccharide linked to N46 of the GP(5) protein is strongly required for virus particle production. The specific infectivities of the mutant viruses were investigated by comparing their infectivity-per-particle ratios with that of wild-type virus. The results showed that the lack of either one or both of the N-linked oligosaccharides on GP(2a) or of the oligosaccharide attached to N53 of GP(5) did not significantly affect the infectivities of the viruses. In contrast, the two recombinant viruses lacking the oligosaccharide bound to N46 exhibited a significantly reduced specific infectivity compared with the wild-type virus. The implications of the differential requirements of the modifications of GP(2a) and GP(5) for PRRSV assembly and infectivity are discussed.

Animals↗
PubMed2005

Characterization of N-linked oligosaccharides in chorion peroxidase of Aedes aegypti mosquito.

A peroxidase is present in the chorion of Aedes aegypti eggs and catalyzes chorion protein cross-linking during chorion hardening, which is critical for egg survival in the environment. The unique chorion peroxidase (CPO) is a glycoprotein. This study deals with the N-glycosylation site, structures, and profile of CPO-associated oligosaccharides using mass spectrometric techniques and enzymatic digestion. CPO was isolated from chorion by solubilization and several chromatographic methods. Mono-saccharide composition was analyzed by HPLC with fluorescent detection. Our data revealed that carbohydrate (D-mannose, N-acetyl D-glucosamine, D-arabinose, N-acetyl D-galactosamine, and L-fucose) accounted for 2.24% of the CPO molecular weight. A single N-glycosylation site (Asn328-Cys- Thr) was identified by tryptic peptide mapping and de novo sequencing of native and PNGase A-deglycosylated CPO using matrix-assisted laser/desorption/ionization time-of-flight mass spectrometry (MALDI/TOF/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). The Asn328 was proven to be a major fully glycosylated site. Potential tryptic glycopeptides and profile were first assessed by MALDI/TOF/MS and then by precursor ion scanning during LC/MS/MS. The structures of N-linked oligosaccharides were elucidated from the MS/MS spectra of glycopeptides and exoglycosidase sequencing of PNGase A-released oligosaccharides. These CPO-associated oligosaccharides had dominant Man3GlcNAc2 and Man3 (Fuc) GlcNAc2 and high mannose-type structures (Man(4-8)GlcNAc2). The truncated structures, Man2GlcNAc2 and Man2 (Fuc) GlcNAc2, were also identified. Comparison of CPO activity and Stokes radius between native and deglycosylated CPO suggests that the N-linked oligosaccharides influence the enzyme activity by stabilizing its folded state.

Aedes↗
PubMed1994

Application of angiogenic oligosaccharides of hyaluronan increases blood vessel numbers in rat skin.

Angiogenic oligosaccharides of hyaluronan were applied to the backs of young, adult male rats and the number of blood vessels, within a depth of 136 microns beneath the base of the epidermis, were evaluated. Application of hyaluronan oligosaccharides significantly increased the mean number of blood vessels/mm skin length in six of 11 treated rats when compared with controls. Application of radiolabeled hyaluronan oligosaccharides to skin of one rat demonstrated a penetration to a depth of approximately 800 microns, suggesting that the blood vessels beneath the epidermis would be exposed to the hyaluronan. Hyaluronan has previously been shown to stimulate endothelial cell proliferation; we demonstrate here that these hyaluronan oligosaccharides also specifically stimulate endothelial cell migration. This action of hyaluronan oligosaccharides may prove useful in retarding blood vessel paucity and degeneration observed during the ageing process and following radiotherapy.

Animals↗
PubMed1990

Comparative study of the N-linked oligosaccharides released from normal human esophageal epithelium and esophageal squamous carcinoma.

N-Linked sugar chains of normal human esophageal epithelium and esophageal squamous carcinoma were quantitatively released as oligosaccharides from their membrane preparations by hydrazinolysis. After being fractionated by serial lectin column chromatography using concanavalin A-Sepharose and Datura stramonium agglutinin-Sepharose, their structures were elucidated by exoglycosidase digestion in combination with methylation analysis. Both normal epithelium and esophageal carcinoma contained bi-, tri- and tetraantennary oligosaccharides as well as high mannose-type oligosaccharides. Interestingly, carcinoma had about 1.6 times larger amounts of tri- and tetraantennary oligosaccharides with the GlcNAc beta 1----4Man alpha 1----and/or the GlcNAc beta 1----6Man alpha 1----linkages than normal epithelium. Tri- and tetraantennary oligosaccharides with N-acetyllactosamine repeating units (the Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4GlcNAc group) were also increased in carcinoma. These data indicated that the altered glycosylation of proteins previously found in transformed rodent cells also occurs widely in human esophageal carcinoma.

Acrylic Resins↗
PubMed1978

Formation of 2-deoxyglucose-containing lipid-linked oligosaccharides. Interference with glycosylation of glycoproteins.

Crude membrane preparations from chick embryo cells catalyse the formation of dolichyl-di-N-acetylchitobiosyl diphosphate [Dol-PP-(GlcNAc)2] from uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). The formation of this glycolipid was stimulated by exogenous dolichyl phosphate and inhibited by tunicamycin. Adding GDP-mannose to the cell-free system containing Dol-PP-(GlcNAc)2 by preincubation led to the formation of a lipid-linked oligosaccharide, containing 8--9 sugar residues. The formation of lipid-linked oligosaccharides was inhibited by GDP-2-deoxy-D-glucose (GDP-dGlc): in this case Dol-PP-(Glc-NAc)2-dGlc accumulated. Subsequent additions of mannosyl residues to this trisaccharide-lipid to form lipid-linked oligosaccharides were not possible. Concomitantly the glycosylation of proteins was blocked. Partially inhibitory conditions were obtained by adding both GDP-dGlc and GDP-Man with an excess of GDP-dGlc. Glycosylation of proteins was observed but the glycopeptides did not contain 2-deoxyglucosyl residues. Also in these cases 2-deoxyglucose-containing glycolipids accumulated. The main glycolipid formed under these conditions was Dol-PP-(GlcNAc)2-Man-dGlc. Lipid-linked oligosaccharides containing 2-deoxyglucose were formed under these conditions, although in small amounts, but were not transferred to protein. So the molecular basis of the inhibitory action of 2-deoxyglucose on glycosylation of protein is the incorporation of 2-deoxyglucosyl residues during early phases of the biosynthesis of the lipid-linked oligosaccharides.

Animals↗
PubMed1979

Urinary excretion of oligosaccharides induced by galactose given orally or intravenously.

The effect of oral administration of galactose, lactose, and sucrose and intravenous injection of galactose on the urinary excretion of blood-group-active oligosaccharides has been studied. Galactose given either as the free sugar, a glycoside (lactose) or a constituent of normal diet was an absolute requirement for the formation and excretion of A-trisaccharide, B-trisaccharide and 2'-fucosylgalactose in blood group A, B and O(H) secretors, respectively. Great individual variation was seen in the amounts of galactose-dependent oligosaccharides excreted. Injection of galactose resulted in excretion of 3-59% of the amount of oligosaccharide formed after oral administration to the same individual. The mean ratio A-trisaccharide/B-trisaccharide was 2.7 in four blood-group-A1B secretors and 0.22 in three A2B secretors and can thus serve as a parameter for chemical differentiation between the two blood groups. The excretion of larger blood-group-active oligosaccharides, including the A-pentasaccharide, the B-pentasaccharide and lactodifucotetraose, that are normal components in urine from, respectively, starved A, B, and H secretors, was about the same after oral administration of galactose or lactose. The B-trisaccharide was the only oligosaccharide detected in plasma after oral galactose administration to a blood-group-B secretor individual. The concentration was 0.38 mg/l of plasma.

ABO Blood-Group System↗
PubMed1979

Determination of Leb-active oligosaccharides in urine of pregnant and lactating women by radioimmunoassay.

Antiserum obtained by immunizing a goat with lacto-N-difucohexaose I, a Leb blood-group hapten, coupled to poly-L-lysine was used in a radioimmunoassay to detect Leb-active oligosaccharides (chiefly lacto-N-difucohexaose I) in urine of 138 pregnant and lactating women of different ABO and Lewis blood groups. Specificity of the method was determined by comparing inhibitory activities of 18 oligosaccharides. Only women who belonged to the Leb blood group excreted Leb-active oligosaccharides in urine. Leb-active oligosaccharides increase during pregnancy, reaching levels up to approximately 70 mumol lacto-N-difucohexaose I equivalents per pmol creatinine in the third trimester and early post-partum period. Excretion varies considerably but tends to be highest in those individuals who strongly express the Leb antigen on their red blood cells or who belong to blood group O. Leb-active oligosaccharides were detected in plasma of a few individuals but at concentrations 1000-fold lower than in urine.

ABO Blood-Group System↗
PubMed1980

Metabolism of lipid-linked oligosaccharide intermediates in rat spleen lymphocytes. Evidence for ectoglycosyltransferase activities.

Double-labelling experiments show that intact lymphocytes as well as lymphocyte homogenates can utilize GDP-[14C]mannose and UDP-N-[3H]acetylglucosamine to synthesize lipid-linked oligosaccharide intermediates. However, the intermediates formed are quantitatively and qualitatively different in the two systems. The amount of dolichyl diphosphate oligosaccharides synthesized in both cases was calculated by using external labelling by sodium boro[3H]hydride reduction of the glycan moiety obtained after mild acid treatment of [14C]mannose-labelled dolichyl diphosphate oligosaccharides. This showed that, due to the liberation of intracellular enzymes, a larger amount of dolichyl diphosphate oligosaccharides was synthesized by homogenate. However, this higher glycosyltransferase activity was not detected by the direct measurement of incorporation of labelled GDP-[14C]mannose and UDP-N-[3H]acetylglucosamine, due to isotopic dilution caused by both endogenous soluble UDP-N-acetylglucosamine and membrane-bound dolichyl phosphate mannose accumulated during the homogenization process. In addition, endogenous UDP-glucose allowed the formation, by homogenate, of glucosylated dolichyl diphosphate oligosaccharides which were not observed with intact cells unless exogenous UDP-glucose was added. These striking differences between the lipid intermediates synthesized by homogenate or by intact cells exclude the possibility that intracellular glycosyltransferases could account for the glycosyltransferase activities observed with whole lymphocyte suspensions. This allows us to conclude that ectoglycosyltransferases involved in the dolichol cycle are present at the outer surface of lymphocytes.

Animals↗
PubMed1981

Specificity of twelve lectins towards oligosaccharides and glycopeptides related to N-glycosylproteins.

Glycopeptides and oligosaccharides of either the N-acetyllactosaminic or the oligomannosidic type derived from glycoproteins containing the N-glycosylamine linkage were used to define the specificity of different lectins (concanavalin A, Lens culinaris agglutinin, Vicia faba agglutinin, Pisum sativum agglutinin, Ricinus communis agglutinins, soybean agglutinin, wheat germ agglutinin, Solanum tuberosum agglutinin, Datura stramonium agglutinin, Lotus tetragonolobus agglutinin, Ulex europeus agglutinin) by studying the inhibition of human red blood cell agglutination by these structures. The results obtained show that lectins considered 'identical' in terms of monosaccharide specificity, possess the ability to recognize fine differences in more complex structures. In fact, different lectins are able to recognize different saccharidic sequences on the same glycan structure. As these sequences are likely to be common to numerous glycoproteins, including cell membrane glycoproteins, the results obtained with lectins in the study of cell surface carbohydrates have to be very carefully interpreted. Moreover, our results confirm previous data on the spatial configuration of the glycan moiety of glycoproteins deduced from the construction of molecular models: the fact that oligosaccharides bearing an alpha-NeuAc-(2 leads to 6)-Gal unit are more powerful inhibitors than oligosaccharides bearing an alpha-NeuAc-(2 leads to 3)-Gal unit could be related to the high rotational freedom of alpha-2,6 linkage; the observation that glycoasparagines, glycopeptides and glycoproteins possess a higher affinity for lectins than the related oligosaccharides could be explained by the fact that the glycan--amino acid linkage leads to structures more rigid than those of the oligosaccharides themselves.

Acetylgalactosamine↗
PubMed1986

The position of the oligosaccharide side-chains of phytohemagglutinin and their accessibility to glycosidases determines their subsequent processing in the Golgi.

Phytohemagglutinin (PHA), the glycoprotein lectin of Phaseolus vulgaris has two types of asparagine-linked oligosaccharides per polypeptide: a high-mannose chain with the formula (Man)8-9(GlcNAc)2 on Asn12 and a modified chain with fewer mannose residues and additional fucose and xylose residues on Asn60. Glycosylation of PHA is a cotranslational process, which occurs in the endoplasmic reticulum, and newly synthesized PHA has two high-mannose chains. Transport of PHA to the protein bodies via the Golgi complex is accompanied by the modification of one of the two high-mannose chains. Why is only one chain modified, while the other remains in the high-mannose configuration? By determining the effect of digestion with various glycosidases (alpha-mannosidase, endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F) on native and denatured PHA we obtained evidence consistent with the interpretation that the accessibility of oligosaccharide chains to modifying enzymes is of major importance in determining whether a high-mannose chain becomes modified or not. The high-mannose chain of mature undenatured PHA is only partially accessible to glycosidases, while PHA obtained from the endoplasmic reticulum has one high-mannose chain, which is readily accessible to alpha-mannosidase and endoglycosidases H and F. We show that this readily accessible chain is in the same position on the polypeptide (Asn60) as the modified oligosaccharide on mature PHA. Thus, accessibility of the oligosaccharide side-chains to processing enzymes in the Golgi determines whether a particular oligosaccharide side-chain is processed or not.

Concanavalin A↗
PubMed1986

Sulphate groups are involved in the antigenicity of keratan sulphate and mask i antigen expression on their poly-N-acetyllactosamine backbones. An immunochemical and chromatographic study of keratan sulphate oligosaccharides after desulphation or nitrosation.

Conditions were established for desulphation of hexa-, octa-, deca- and larger oligosaccharides derived from corneal keratan sulphate after treatment with endo-beta-galactosidase. The antigenicities of the desulphated oligosaccharides were compared with those of the native oligosaccharides in chromatogram binding, plastic-plate binding or inhibition of binding assays using a novel microimmunochemical approach with oligosaccharide-lipid conjugates (neoglycolipids). The results clearly show that sulphate residues are essential components of the antigenic determinant(s) recognised by three monoclonal antibodies to keratan sulphate, 5-D-4, 1-B-4 and MZ15, but they mask the i antigen activity of the linear poly-(N-acetyllactosamine) backbones of this glycosaminoglycan. Immunochemical assays, before and after beta-N-acetylglucosaminidase treatment of desulphated linear hexa-, octa- and decasaccharides derived from keratan sulphate, indicate that for reaction with one anti-i antibody, Den, there is an absolute requirement for the non-reducing beta-galactosyl residue of the i antigen structure to be in the terminal position, but with a second anti-i antibody, Tho, there is in addition some reactivity with the i antigen structure having an N-acetylglucosamine residue at the non-reducing end. The chromatographic properties after desulphation or nitrosation of a minor keratan sulphate oligosaccharide (a dodecasaccharide), which reacts especially well with antibody 5-D-4, have provided the first evidence for the presence of glucosamine residues that may be N-sulphated in corneal keratan sulphate.

Animals↗
PubMed1986

Structural analysis of the asparagine-linked oligosaccharides of rat haptoglobin metabolically labeled in a hepatocyte culture system.

We analyzed the asparagine-linked oligosaccharide chains of rat haptoglobin which were synthesized and secreted by hepatocytes in primary culture. When the cells were incubated with either [3H]mannose, [3H]galactose, or [3H]fucose, all the radioactive precursors were incorporated into the beta subunit of haptoglobin. [3H]Mannose-labeled haptoglobin was purified from the culture medium by immunoaffinity chromatography, and [3H]oligosaccharides were prepared by strong alkali-borohydride treatment. The oligosaccharides obtained were analyzed by anion-exchange high-performance liquid chromatography, concanavalin-A--Sepharose chromatography and Bio-Gel P-4 chromatography before and after sequential exoglycosidase digestions. The oligosaccharides labeled with [3H]fucose or [3H]galactose were also characterized by the above methods. The results indicate that rat haptoglobin contains two complex-type oligosaccharide chains in each beta subunit; one with a possible structure of ( +/- NeuAc----Gal beta----GlcNAc beta----)3(Man alpha----)2 Man beta----GlcNAc----( +/- Fuc alpha----)GlcNAc and the other with ( +/- NeuAc----Gal beta----GlcNAc beta----Man alpha----)2 Man beta----GlcNAc----( +/- Fuc alpha----)GlcNAc.

Animals↗
PubMed1994

Isolation and structural analysis of oligosaccharide phosphates containing the complete carbohydrate chain of the lipopolysaccharide from Vibrio cholerae strain H11 (non-O1).

For the first time, an oligosaccharide has been prepared comprising the lipid A backbone, the core oligosaccharide and one repeating unit of the O-specific polysaccharide (O-chain) of a lipopolysaccharide. Lipopolysaccharide from Vibrio cholerae strain H11 (non-O1) was deacylated and the products were separated by high-performance anion-exchange chromatography. Major fractions were a hexadecasaccharide trisphosphate 1, representing the core-lipid A oligosaccharide substituted by one modified repeating unit of the O-antigenic polysaccharide, a dodecasaccharide trisphosphate 2 and an undecasaccharide trisphosphate 3, representing the core-lipid A region. Oligosaccharide 1 originated from beta-elimination upon alkaline hydrolysis of alpha-galacturonic acid of the O-chain; oligosaccharides 2 and 3 were most likely obtained from naturally occurring lipopolysaccharide species carrying no O-chain. The structures of these compounds were elucidated on the basis of monosaccharide composition, and NMR investigations comprising correlation spectroscopy, total correlation spectroscopy and nuclear Overhauser enhancement spectroscopy experiments, as well as heteronuclear 13C, 1H correlation spectroscopy. The structures are as follows: [formula: see text] where R is beta-L-threo-hex-4-enuronopyranosyl-(1-4)-alpha-Neu-(2-3)-beta-Gal A-(1-3)- beta-QuiN-(1-4)-beta-Sedf-(2- in 1, beta-Sedf-(2- in 2, and H in 3. Where not stated otherwise, sugars are pyranoses of the D-series. Hep is L-glycero-D-manno-heptose, QuiN is 2-amino-2,6-dideoxy-glucose, Kdo is 3-deoxy-D-manno-2-octulosonic acid, Sed is D-altro-heptulose and GalA is galacturonic acid.

Carbohydrate Sequence↗
PubMed1997

Human milk oligosaccharides: only the breast.

Over 100 years ago it was first deduced that a major component of human milk must be an unidentified carbohydrate that was not found in cows milk. At first this was thought to be a form of lactose and was called gynolactose. We now know that this was not a single carbohydrate but a complex mixture of approximately 130 different oligosaccharides. Although small amounts of a few oligosaccharides have been found in the milk of other mammals, this rich diversity of sugars is unique to human milk. The oligosaccharide content of human milk varies with the infant's gestation, the duration of lactation, diurnally and with the genetic makeup of the mother. Milk oligosaccharides have a number of functions that may protect the health of the breast fed infant. As they are not digested in the small intestine, they form the 'soluble' fibre of breast milk and their intact structure is available to act as competitive ligands protecting the breast-fed infant from pathogens. There is a growing list of pathogens for which a specific oligosaccharide ligand has been described in human milk. They are likely to form the model for future therapeutic and prophylactic anti-microbials. They provide substrates for bacteria in the infant colon and thereby contribute to the difference in faecal pH and faecal flora between breast and formula-fed infants. They may also be important as a source of sialic acid, essential for brain development.

Female↗
PubMed1982

Concanavalin A receptors associated with rat brain synaptic junctions are high mannose-type oligosaccharides.

Glycoproteins were isolated from a rat brain synaptic junction fraction by affinity chromatography on Concanavalin A-agarose. The isolated glycoproteins were digested with pronase and radiolabeled with 125I-Bolton Hunter reagent, and 125I-Concanavalin A-binding glycopeptides were isolated by chromatography on Concanavalin A-agarose. Treatment of the 125I-Concanavalin A-binding glycopeptides with either alpha-mannosidase or endo-beta-N-acetylglucosaminidase-C11 abolished their interaction with Concanavalin A. The pronase digest was reacted with endo-beta-N-acetylglucosaminidase-C11 and released oligosaccharides were reduced with NaB3H4. Following affinity chromatography on Concanavalin A-agarose, Concanavalin A-binding [3H]oligosaccharides were chromatographed on Biogel P4. Two major oligosaccharides corresponding to standard carbohydrates containing eight and five mannose residues were identified. Treatment of these oligosaccharides with alpha-mannosidase converted them to smaller saccharides having a mobility on Biogel P4 columns equal to the standard disaccharide mannose-beta-1-4-N'-acetylglucosamine. These results demonstrate that the Concanavalin A receptor activity associated with CNS synaptic junctions resides in asparagine-linked oligosaccharides of the high-mannose type.

Animals↗
PubMed2005

Growth of various intestinal bacteria on alternansucrase-derived oligosaccharides.

AIMS: To determine whether alternansucrase (ASR)-derived oligosaccharides can support the in vitro growth of various intestinal bacteria. METHODS AND RESULTS: Growth was assessed from each culture after incubation in a medium containing ASR-derived oligosaccharide as sole carbohydrate source. Most of the Bifidobacterium spp. tested showed growth on all five of the oligosaccharides tested while the Lactobacillus spp., Bacteroides thetaiotaomicron, coliforms and pathogenic bacteria displayed no or little growth. CONCLUSIONS: The ASR-derived oligosaccharides were selectively utilized by many of the Bifidobacterium spp. tested but did not support significant growth of the Lactobacillus spp., Bact. thetaiotaomicron, coliforms and pathogenic bacteria tested. SIGNIFICANCE AND IMPACT OF THE STUDY: Alternansucrase-derived oligosaccharides are a potential source of new prebiotics.

Animals↗
PubMed2004

Co-localization of beta1,6-branched oligosaccharides and coarse melanin in macrophage-melanoma fusion hybrids and human melanoma cells in vitro.

Fusion hybrids between normal macrophages and Cloudman S91 melanoma cells were shown earlier to have increased metastatic potential, along with high expression of beta1,6-N-acetylglucosaminyltransferase V and beta1,6-branched oligosaccharides. Curiously, hybrids, but not parental melanoma cells, also produced 'coarse melanin'- autophagic vesicles with multiple melanosomes. As beta1,6-branched oligosaccharides were known to be associated with metastasis, and coarse melanin had been described in invasive human melanomas, we looked for potential relationships between the two. Using lectin- and immunohistochemistry, we analyzed cell lines producing coarse melanin for beta1,6-branched oligosaccharides: gp100/pmel-17 (a melanosomal structural component) and CD63 (a late endosome/lysosome component associated with melanoma and certain other human cancers). Cell lines used in this study were (i) hybrid 94-H48, a highly metastatic, macrophage-melanoma experimental fusion hybrid; (ii) 6(neo) mouse melanoma cells, the weakly metastatic, parental fusion partner; and (iii) SKmel-23, a human melanoma cell line derived from a metastasis. Coarse melanin granules were prominent both in hybrids and in SKmel-23 cells, and co-localized with stains for beta1,6-branched oligosaccharides, gp100/pmel 17, and CD63. This is the first report of this phenotype being expressed in vitro, although co-expression of beta1,6-branched oligosaccharides and coarse melanin was recently shown to be a common and pervasive characteristic in archival specimens of human melanomas, and was most prominent in metastases. The results suggest that pathways of melanogenesis in melanoma may differ significantly from those in normal melanocytes. In vitro expression of this phenotype provides new biological systems for more detailed analyses of its genesis and regulation at the molecular genetic level.

Animals↗