BIOSYNTHESIS OF HUMAN COLONIC MUCIN - MUC2 IS THE PROMINENT SECRETORY MUCIN
BIOSYNTHESIS OF HUMAN COLONIC MUCIN - MUC2 IS THE PROMINENT SECRETORY MUCIN
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DOI：
10.1016/0016-5085(94)90537-1
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发表时间：
1994-11-01
期刊：
影响因子：
29.4
通讯作者：
DEKKER, J
中科院分区：
文献类型：
--
作者：
TYTGAT, KMAJ;BULLER, HA;DEKKER, J
背景/目的：人类结肠上皮产生大量粘蛋白。本研究的目的是检查粘蛋白的生物合成在人类结肠。方法：采用氯化铯密度梯度法分离人结肠粘蛋白，制备多克隆抗血清。用S-35标记的氨基酸或[S-35]硫酸盐标记结肠外植体，随后进行免疫沉淀和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE），研究结肠粘蛋白的生物合成。结果：所制备的多克隆抗血清特异性识别结肠粘蛋白，主要与肽表位反应。生物合成脉冲/追踪实验显示约600千道尔顿的S-35-氨基酸标记的粘蛋白前体，其转化为成熟的、糖基化的和硫酸化的粘蛋白，随后分泌到培养基中。该成熟粘蛋白与分离的结肠粘蛋白共迁移，在SDS-PAGE上具有550千道尔顿的表观分子量，而凝胶过滤表明分子量实际上大得多。与抗Muc 2抗血清的独立免疫沉淀显示与600千道尔顿前体的交叉反应性。结论：这些结果首次显示了分泌性结肠粘蛋白的生物合成。这种粘蛋白被合成为约600千道尔顿的前体蛋白，其在糖基化后被分泌为在SDS-PAGE上具有550千道尔顿的表观分子量的糖蛋白。这种粘蛋白很可能是Muc 2。
Background/Aims: Human colonic epithelium produces large amounts of mucin. The aim of this study was to examine mucin biosynthesis in the human colon. Methods: Human colonic mucin was isolated using CsCl density gradients, and polyclonal antiserum was raised. Biosynthesis of colonic mucins was studied by labeling colonic explants with S-35-labeled amino acids or [S-35]sulfate and subsequent immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results: The polyclonal antiserum specifically recognized colonic mucin, primarily reacting with peptide epitopes. Biosynthetic pulse/chase experiments showed a S-35-amino acid-labeled mucin precursor of about 600 kilodaltons, which was converted into a mature, glycosylated, and sulfated mucin and subsequently secreted into the medium. This mature mucin comigrated with isolated colonic mucin with an apparent molecular weight of 550 kilodaltons on SDS-PAGE, whereas gel filtration indicated that the molecular weight is actually much larger. Independent immunoprecipitation with an anti-Muc2 antiserum showed cross-reactivity with the 600-kilodalton precursor. Conclusions: These results show the biosynthesis of a secretory colonic mucin for the first time. This mucin is synthesized as a precursor protein of approximately 600 kilodaltons, which, after glycosylation, is secreted as a glycoprotein with an apparent molecular weight of 550 kilodaltons on SDS-PAGE. It is very likely that this mucin is Muc2.