Disease relevance of MUC

• Diet influences the colonisation of Campylobacter jejuni and distribution of mucin carbohydrates in the chick intestinal tract [1].
• PURPOSE: To determine whether the relative amounts of mucin mRNA in the conjunctival epithelium and mucin protein in the tears are altered in patients with Sjögren syndrome compared with healthy individuals [2].
• The results implicate Mub as a cell-surface protein that is involved in Lactobacillus interactions with mucin and in colonization of the digestive tract [3].
• Inhibition by tunicamycin of mucin synthesis, not morphological changes, in epidermis during retinol-induced mucous metaplasia of chick embryonic cultured skin [4].
• The expression of T-antigen in colon cancer tissue was detected by two T-disaccharide specific probes, chicken anti-T-yolk antibody (IgY) and Artocarpus integrifolia lectin (AIL) and was found to be more pronounced in both the secreted mucin as well as the cytoplasmic mucin deposits [5].

High impact information on MUC

• A uniform labeling was observed over the first and several subsequent cis Golgi cisternae and over the last (duodenal goblet cells) or the two last (colonic goblet cells) trans Golgi cisternae as well as forming and mature mucin droplets [6].
• The O-linked oligosaccharides of mucin-type glycoproteins contain N-acetyl-D-galactosamine (GalNAc) that is not found in N-linked glycoproteins [6].
• Secretion of lectin may occur in conjunction with mucin because both are localized in the secretory vesicles and CLL-1 and CLL-11 apparently bind to purified chicken intestinal mucin, which is a potent inhibitor of their hemagglutination activities [7].
• The two lactose-binding lectins found in adult chicken intestine, chicken-lactose-lectin-1 (CLL-1) and chicken-lactose-lectin-11 (CLL-11), were localized within the vesicles of the mucin-secreting goblet cells by indirect immunofluorescence and immunoperoxidase staining methods [7].
• The mucin is six orders of magnitude more potent than lactose as a hemagglutination inhibitor of CLL-1 or CLL-11 on a molar basis, and three orders of magnitude more potent when expressed per mole of hexose [7].

Biological context of MUC

• Mucin gene expression and mucin content in the chicken intestinal goblet cells are affected by in ovo feeding of carbohydrates [8].

Anatomical context of MUC

• Relative amounts of intestinal mucin mRNA and protein increased in the duodenum and jejunum of starved chicks, and mucus adherent layer thickness decreased throughout the small intestine [9].
• These results suggest that CLL-11, and perhaps CLL-1, are secreted from the goblet cells along with mucin [7].
• When virally mediated Hoxd-13 is misexpressed in the primitive midgut mesoderm, there is a transformation of the endoderm to the morphology and mucin content of the hindgut [10].
• During week 17.5, the follicle-associated epithelium began to lose its endocytic capability, and mucin droplets appeared in the follicular medulla initiating the large mucoid cysts that were seen in the later phases of involution [11].
• Directional Ca2+ effect on stimulation of mucin secretion from chicken trachea in vitro [12].

Associations of MUC with chemical compounds

• A striking feature of syndecan 3 is an extensive (182 amino acid) threonine, serine, and proline (T+S+P)-rich domain that closely resembles T+S+P-rich regions in several mucin-like proteins in which O-linked oligosaccharides are bound to the threonine and serine residues [13].
• 5. The transport of Ca2+ from the mucosa into the lumen in the form of mucin-bound Ca2+ appeared to play a significant role in the regulation of Ca2+ efflux from the tissue under increased Ca2+ influx or efflux conditions resulting from interventions with serosal and luminal [Ca2+] [14].
• The effects of calcium and calcium ionophore A23187 on mucin secretion and potential difference in the isolated chicken trachea [proceedings] [15].
• These results indicate that both probiotic and AGP altered processes of mucin biosynthesis and/or degradation mediated via changes in the intestinal bacterial populations [16].
• In AGP-fed chicks, the villous surface area was increased in the jejunum, goblet cell density was greater in the jejunum and ileum, and mucin glycoprotein levels in the duodenum were lower than in the other groups (P < 0.05) [16].

Analytical, diagnostic and therapeutic context of MUC

• Electron microscopy investigation on the shape of alpha-dystroglycan suggests that the core protein consists of two roughly globular domains connected by a segment which most likely corresponds to a mucin-like central region also predicted by sequence analysis on mammalian isoforms [17].
• Enhanced expression of the mucin mRNA was found at the day of hatch in chicks that received carbohydrate solution into the amnionic fluid in comparison with the control group [8].
• A lectin was purified from the seaweed Gracilaria cornea by hydrophobic interaction chromatography on phenyl-Sepharose CL-4B followed by affinity chromatography on immobilized mucin [18].
• Primary cell cultures enriched in mucin-producing cells and basal cells were established from the trachea of the domestic fowl [19].

References