Disease relevance of MUC7

• We have hypothesized that changes in the glycosylation of key tracheal mucins such as MUC5B and MUC7 might increase the risk of pulmonary disease in CF patients [1].
• Altered sialyl- and fucosyl-linkage on mucins in cystic fibrosis patients promotes formation of the sialyl-Lewis X determinant on salivary MUC-5B and MUC-7 [1].
• The highest frequencies of positive RT-PCR tests in breast tumor extracts were observed for MUC5B (7/15) and MUC7 (5/12) [2].
• In conclusion, MUC7 12-mer appears to be a promising candidate as an antifungal agent for oral candidiasis [3].
• The role of crude human saliva and purified salivary MUC5B and MUC7 mucins in the inhibition of Human Immunodeficiency Virus type 1 in an inhibition assay [4].

High impact information on MUC7

• MUC5B, MUC7, and MUC8 transcripts were not detected [5].
• To begin to understand the molecular mechanisms responsible for controlling MUC7 gene expression, we analyzed the promoter activity of MUC7 5'-flanking region in a human lung epithelial cell line A549 [6].
• Functional Analysis of Human MUC7 Mucin Gene 5'-Flanking Region in Lung Epithelial Cells [6].
• MUC7 gene expression is tissue- and cell-specific, with dominant expression in salivary gland acinar cells [6].
• The effect of LPS on MUC7 gene expression was also studied in the airway tissues of MUC7 gene transgenic mice [7].

Biological context of MUC7

• In contrast, MUC5AC, MUC5B, and MUC7 are expressed at later gestational ages concomitant with epithelial cytodifferentiation [8].
• The clinical implication of the up-regulation of some MUC genes toward the anastomotic site in patients with an enteroplasty and the aberrant expression of MUC5AC - MUC7 by transposed segments is at present unclear [9].
• MUC7 gene expression and genetic polymorphism [10].
• Genetic polymorphism studies of MUC7 by PCR and Southern blot analysis revealed the presence of a limited variable number of tandem repeats (VNTR) polymorphism [10].
• This study examined differential expression of several mucin genes in the human submandibular gland and trachea, MUC7 tissue and species specificity, and MUC7 genetic polymorphism [10].

Anatomical context of MUC7

• Northern blot analysis confirmed the expression of MUC7 in the human trachea and MUC4 in the human submandibular gland [10].
• Northern blot analysis also demonstrated that MUC7 is not expressed in the submandibular/sublingual gland complexes of hamster, mouse and rat [10].
• MUC7 was present only in columnar epithelial cells of the efferent tear duct system [11].
• PURPOSE: To determine whether human conjunctival epithelium expresses any of the human mucin genes designated MUC2 through MUC7 [12].
• In contrast MUC7 is expressed in serous cells of salivary glands except the parotid glands [13].

Associations of MUC7 with chemical compounds

• Upon LPS stimulation, the overexpressed MUC7 remains confined to the serous glands [7].
• By immunohistochemistry, MUC7 glycoprotein was localized in tracheal submucosa within the serous cells [7].
• In vitro synergic antifungal effect of MUC7 12-mer with histatin-5 12-mer or miconazole [14].
• Antifungal activities of MUC7 12-mer in combination with other compounds [histatin-5 (Hsn5) 12-mer: AKRHHGYKRKFH, amphotericin B or miconazole] against C. albicans and C. neoformans were determined by chequerboard assays and confirmed by killing assays [14].
• Two monoclonal antibodies, directed against gp-340, were characterized. mAb 213-1 reacted with sialic acid epitopes and cross-reacted with MUC7 [15].

Other interactions of MUC7

• In the submucosal glands, MUC2 mRNAs are located in both mucous and serous cells, whereas MUC5B and MUC7 mRNAs are expressed in mucous and in serous cells, respectively [8].
• MUC6 was positive in 13/40 tumors, and both MUC2 and MUC7 in only 2/40 tumors [16].
• Although a complete protein sequence is known for only three human mucins (MUC1, MUC2, and MUC7), common motifs have been identified in many mucins [17].
• MUC7 12-mer (residues 40-51 of the parent MUC7) peptide, having the optimal size and a net charge of +6, was found to be anticandidal in human saliva (clarified and unclarified), and its candidacidal potency was found to be superior to that of histatin 5 12-mer (Hsn5 12-mer) [3].
• This active coping response was associated with an enhanced secretion ( microg/min, controlling for salivary flow rate) of MUC7, lactoferrin, alpha-amylase, and total salivary protein [18].

Analytical, diagnostic and therapeutic context of MUC7

• Of the nine mucin genes that have been characterized, only MUC1 and MUC7 have been fully sequenced, and their transcripts can be detected as distinct bands of predicted size by Northern blot analysis [19].
• Southern blot analysis suggested the presence of a MUC7 homologue in monkey genomic DNA [10].
• MUC7 protein was detected by Western blot analysis [20].
• In situ hybridization with PCR product-based riboprobes was used to locate MUC7 transcripts in the lacrimal gland [20].
• In a sample of whole human saliva, reactions of both isoforms of MUC7 were detected by autoradiography, as bands of 85 and 115 kD, and densitogram analysis also demonstrated reaction with MUC5B [21].

References