Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida 32610-3003, USA.
J Histochem Cytochem. 2010 Feb;58(2):141-56. doi: 10.1369/jhc.2009.954891.
The recently identified gene Muc19/Smgc encodes two diverse splice variants, Smgc (submandibular gland protein C) and Muc19 (mucin 19). Muc19 is a member of the large gel-forming mucin family and is an exocrine product of sublingual mucous salivary glands in mice. SMGC is a transiently expressed secretion product of developing rodent submandibular and sublingual glands. Little is known about the expression of Muc19/Smgc gene products in other murine salivary and non-salivary tissues containing the mucous cell phenotype. Muc19 expression was therefore initially assessed by RT-PCR and immunohistochemistry. As a complementary approach, we developed a knockin mouse model, Muc19-EGFP, in which mice express a fusion protein containing the first 69 residues of Muc19 followed by enhanced green fluorescent protein (EGFP) as a marker of Muc19 expression. Results from both approaches are consistent, with preferential Muc19 expression in salivary major and minor mucous glands as well as submucosal glands of the tracheolarynx and bulbourethral glands. Evidence also indicates that individual mucous cells of minor salivary and bulbourethral glands produce another gel-forming mucin in addition to Muc19. We further find tissue expression of full-length Smgc transcripts, which encode for SMGC, and are restricted to neonatal tracheolarynx and all salivary tissues.
最近鉴定的基因 Muc19/Smgc 编码两种不同的剪接变体，Smgc（下颌下腺蛋白 C）和 Muc19（粘蛋白 19）。Muc19 是大型凝胶形成粘蛋白家族的成员，是小鼠舌下粘液唾液腺的外分泌产物。SMGC 是发育中的鼠下颌下腺和舌下腺的短暂表达的分泌产物。关于 Muc19/Smgc 基因产物在含有粘液细胞表型的其他鼠唾液和非唾液组织中的表达知之甚少。因此，最初通过 RT-PCR 和免疫组织化学评估 Muc19 表达。作为一种补充方法，我们开发了一种 Muc19-EGFP 敲入小鼠模型，其中小鼠表达一种融合蛋白，该融合蛋白包含 Muc19 的前 69 个残基，后面跟着增强型绿色荧光蛋白（EGFP）作为 Muc19 表达的标志物。两种方法的结果都是一致的，唾液主要和次要粘液腺以及气管喉和尿道球腺的粘膜下腺中优先表达 Muc19。有证据表明，除了 Muc19 之外，次要唾液腺和尿道球腺的单个粘液细胞还产生另一种凝胶形成粘蛋白。我们进一步发现全长 Smgc 转录本的组织表达，其编码 SMGC，并局限于新生儿气管喉和所有唾液组织。
