Liu Bing, Lague Jessica R, Nunes David P, Toselli Paul, Oppenheim Frank G, Soares Rodrigo V, Troxler Robert F, Offner Gwynneth D
Department of Periodontology, Boston University Medical Center, Boston, Massachusetts 02118, USA.
J Histochem Cytochem. 2002 Jun;50(6):811-20. doi: 10.1177/002215540205000607.
Mucins are high molecular weight glycoproteins secreted by salivary glands and epithelial cells lining the digestive, respiratory, and reproductive tracts. These glycoproteins, encoded in at least 13 distinct human genes, can be subdivided into gel-forming and membrane-associated forms. The gel-forming mucin MUC5B is secreted by mucous acinar cells in major and minor salivary glands, but little is known about the expression pattern of membrane-associated mucins. In this study, RT-PCR and Northern blotting demonstrated the presence of transcripts for MUC1 and MUC4 in both parotid and submandibular glands, and in situ hybridization localized these transcripts to epithelial cells lining striated and excretory ducts and in some serous acinar cells. The same cellular distribution was observed by immunohistochemistry. Soluble forms of both mucins were detected in parotid secretion after immunoprecipitation with mucin-specific antibodies. These studies have shown that membrane-associated mucins are produced in both parotid and submandibular glands and that they are expressed in different cell types than gel-forming mucins. Although the function of these mucins in the oral cavity remains to be elucidated, it is possible that they both contribute to the epithelial protective mucin layer and act as receptors initiating one or more intracellular signal transduction pathways.
黏蛋白是由唾液腺以及消化、呼吸和生殖道的上皮细胞分泌的高分子量糖蛋白。这些糖蛋白由至少13种不同的人类基因编码，可分为凝胶形成型和膜相关型。凝胶形成型黏蛋白MUC5B由大、小唾液腺的黏液腺泡细胞分泌，但关于膜相关黏蛋白的表达模式知之甚少。在本研究中，逆转录聚合酶链反应（RT-PCR）和Northern印迹法证明了腮腺和颌下腺中存在MUC1和MUC4的转录本，原位杂交将这些转录本定位到纹状管和排泄管的上皮细胞以及一些浆液性腺泡细胞中。免疫组织化学观察到相同的细胞分布。用黏蛋白特异性抗体免疫沉淀后，在腮腺分泌物中检测到两种黏蛋白的可溶性形式。这些研究表明，膜相关黏蛋白在腮腺和颌下腺中均有产生，并且它们在与凝胶形成型黏蛋白不同的细胞类型中表达。尽管这些黏蛋白在口腔中的功能仍有待阐明，但它们有可能既有助于上皮保护性黏蛋白层的形成，又作为启动一种或多种细胞内信号转导途径的受体。
