Mucins are heavily glycosylated proteins characterized by high molecular weight and heterogeneous structure. Mucin genes are expressed in a tissue- or epithelium-specific manner. Although mucins are known to be important structural components of the mucociliary transport system that protects epithelium against invading microorganisms, very little is known about mucin gene expression unique to the middle ear. This study demonstrated that middle ear messenger RNA specifically hybridized with rat MUC2 and human MUC2 (SMUC-41) complementary DNA probes. MUC3 and MUC5AC mucin genes, dominantly expressed in rodent intestine and trachea, were not detected in the rat middle ears in this study. The middle ear MUC2 messenger RNA harvested by lavage was characterized by a single transcript — unlike its counterpart in intestine and airways, which is characterized by polydispersity — suggestive of a better method for RNA analysis. It was concluded that rat middle ears possess a MUC2 mucin gene or homologue of human MUC2 (SMUC-41).
ToribaraNWGumJRCulhanePJ. MUC-2 human small intestinal mucin gene structure. J Clin Invest1991; 88: 1005–13.
2.
ReddyMSMurphyTFFadenHSBernsteinJM. Middle ear mucin glycoprotein: Purification and interaction with nontypeable Haemophilus influenzae and Moraxella catarrhalis. Otolaryngol Head Neck Surg1997; 116: 175–80.
3.
CarnoyCScharfmanAVan BrusselELamblinGRamphalRRousselP. Pseudomonas aeruginosa outer membrane adhesins for human respiratory mucus glycoproteins. Infect Immun1994; 62: 1896–900.
4.
FlormanHMWassarmanPM. O-linked oligosaccharides of mouse ZP3 account for its sperm receptor activity. Cell1985; 41: 313–24.
5.
RosenSD. Cell surface lectins in the immune system. Semin Immunol1993; 5: 237–47.
6.
DekkerJAelmansPHStrousGJ. The oligomeric structure of rat and human gastric mucins. Biochem J1991; 277: 423–7.
7.
WesleyAMantleMManDQureshiRForstnerGForstnerJ. Neutral and acidic species of human intestinal mucin: Evidence for different core peptides. J Biol Chem1985; 260: 7955–9.
8.
GumJRByrdJCHicksJWToribaraNWLamportDTKimYS. Molecular cloning of human intestinal mucin cDNA: Sequence analysis and evidence for genetic polymorphism. J Biol Chem1989; 264: 6480–7.
GendlerSJSpicerAP. Epithelial mucin genes. Annu Rev Physiol1995; 57: 607–34.
11.
ShekelsLLHunninghakeDATisdaleAS. Cloning and characterization of mouse intestine MUC3 mucin: 3′ sequence containing EGF domain. Biochem J1998; 330: 1301–8.
12.
ShankarVPichanPEddyRLJr. Chromosomal location of a human mucin gene (MUC8) and cloning of the cDNA corresponding to the carboxy terminus. Am J Respir Cell Mol Biol1997; 16: 232–41.
13.
BobekLATsaiHBiesbrockARLevineMJ. Molecular cloning, sequence and specificity of expression of the gene encoding the low molecular weight human salivary mucin (MUC7). J Biol Chem1993; 268: 20563–9.
14.
DekkerJStrousGL. Covalent oligomerization of rat gastric mucin occurs in the rough endoplasmic reticulum, is N-glycosylation-dependent, and precedes initial O-glycosylation. J Biol Chem1990; 265: 18116–22.
15.
CarlstedtIHerrmannAHovenbergH. “Soluble” and “insoluble” mucins — Identification of distinct populations. Biochem Soc Trans1995; 23: 845–51.
16.
SheehanJKThorntonDJHowardMCarlstedtICorfieldAPParaskevaC. Biosynthesis of the MUC2 mucin: Evidence for a slow assembly of fully glycosylated units. Biochem J1996; 315: 1055–60.
17.
ChomczynskiPSacchiN. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem1987; 162: 156–9.
18.
SambrookJFritschEFManiatisT. Molecular cloning: a laboratory manual. 2nd ed. Cold Spring Harbor, NY: Cold Spring Harbor Press, 1989.
19.
OhmoriHDohrmanAFGallupM. Molecular cloning of the amino-terminal region of a rat MUC2 mucin gene homologue. Evidence for expression in both intestine and airway. J Biol Chem1994; 269: 17833–40.
20.
XuGHuanL-JKhatriI. cDNA for the carboxyl terminal region of a rat intestinal mucin-like peptide. J Biol Chem1992; 267: 5401–7.
21.
TsoJYSunXHKaoTHReeceKSWuR. Isolation and characterization of rat and human glyceraldehyde-3-phosphate dehydrogenase cDNAs: Genomic complexity and molecular evolution of the gene. Nucleic Acids Res1985; 13: 2485–502.
22.
LimDJ. Normal and pathological mucosa of the middle ear and eustachian tube. Clin Otolaryngol1979; 4: 213–32.
23.
JanyBGallupMTsudaTBasbaumC. Mucin gene expression in rat airways following infection and irritation. Biochem Biophys Res Commun1991; 181: 1–8.
24.
AudieJPJaninAPorchetNCopinMCGosselinBAubertJP. Expression of human mucin genes in respiratory, digestive, and reproductive tracts ascertained by in situ hybridization. J Histochem Cytochem1993; 41: 1479–85.
25.
LinJKimYJuhnSK. Increase of mucous glycoprotein secretion by tumor necrosis factor alpha via a protein kinase C—dependent mechanism in cultured chinchilla middle ear epithelial cells. Ann Otol Rhinol Laryngol1998; 107: 213–9.
26.
FitzGeraldJEGreenGGStaffordFWBirchallJPPearsonJP. Characterization of human middle ear mucus glycoprotein in chronic secretory otitis media (CSOM). Clin Chim Acta1987; 169: 281–97.
27.
WiseRJPittmanDDHandinRIKaufmanRJOrkinSH. The propeptide of von Willebrand factor independently mediates the assembly of von Willebrand multimers. Cell1988; 52: 229–36.
28.
JournetAMSaffaripourSWagnerDD. Requirement for both D domains of the propolypeptide in von Willebrand factor multimerization and storage. Thromb Haemost1993; 70: 1053–7.
29.
CarrieSHuttonDABirchallJPGreenGGPearsonJP. Otitis media with effusion: Components which contribute to the viscous properties. Acta Otolaryngol (Stockh)1992; 112: 504–11.
30.
MajimaYJinCSTakeuchiKHamaguchiYSakakuraYJuhnSK. Rheological properties of middle ear mucus in relation to goblet cell population in cat. Acta Otolaryngol [Suppl] (Stockh) 1991(suppl 483): 11–6.
31.
DebailleulVLaineAHuetG. Human mucin genes MUC2, MUC3, MUC4, MUC5AC, MUC5B, and MUC6 express stable and extremely large mRNAs and exhibit a variable length polymorphism. J Biol Chem1998; 273: 881–90.
32.
SwallowDMGendlerSGriffithsBCorneyGTaylor-PapadimitriouJBramwellME. The human tumor-associated epithelial mucins are coded by an expressed hypervariable gene locus PUM. Nature1987; 328: 82–4.
33.
GendlerSJLancasterCATaylor-PapadimitriouJ. Molecular cloning and expression of human tumor-associated polymorphic epithelial mucin. J Biol Chem1990; 265: 15286–93.
34.
GriffithsBMatthewsDJWestL. Assignment of the polymorphic intestinal mucin gene (MUC2) to chromosome-11p15. Ann Hum Genet1990; 54: 277–85.
35.
JeffreysAJWilsonVTheinSL. Hypervariable “minisatellite” regions in human DNA. Nature1985; 314: 67–73.
