Identification and expression of human epiglycanin/MUC21: A novel transmembrane mucin
Identification and expression of human epiglycanin/MUC21: A novel transmembrane mucin
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DOI：
10.1093/glycob/cwm118
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发表时间：
2008-01-01
期刊：
影响因子：
4.3
通讯作者：
Irimura, Tatsuro
中科院分区：
文献类型：
--
作者：
Itoh, Yuichi;Kamata-Sakurai, Mika;Irimura, Tatsuro
小鼠表聚糖蛋白的人类直系同源基因是一种在乳腺癌 TA3-Ha 细胞上表达的粘蛋白，但在 TA3-St 细胞上不表达，通过同源性搜索鉴定出小鼠表聚糖蛋白 cDNA 片段，该片段通过 TA3-Ha 和 TA3-St 细胞之间的代表性差异分析鉴定。该基因的开放阅读框是从人宫颈癌ME-180细胞中克隆的。它由一个粘蛋白结构域和一个干结构域、一个跨膜结构域和一个细胞质尾部组成，该粘蛋白结构域具有 28 个不同的串联重复序列（每个重复序列有 45 个核苷酸），每个重复序列对应于富含苏氨酸/丝氨酸的肽。克隆的带有FLAG序列的cDNA在K562细胞中表达。免疫沉淀与细胞质尾特异性多克隆抗体的结合以及使用抗 FLAG 抗体和凝集素的蛋白质印迹分析揭示了粘蛋白样成分作为基因产物。利用组织cDNA文库分析表明，该基因在所测试的16个正常组织中的肺、大肠、胸腺和睾丸中表达。对来自细胞质尾部的合成肽具有特异性的多克隆抗体，在测试其与正常肺组织的反应性时，与支气管和细支气管的上皮细胞发生反应，但不与肺泡发生反应。所测试的所有 24 个肺腺癌样本均与该抗体发生反应，而在 24 个鳞状细胞肺癌样本中仅观察到了 2 个样本有反应性，而在 24 个小细胞肺癌样本中则没有观察到反应性。这是一种新型跨膜粘蛋白，命名为MUC21。
The gene for the human orthologue of mouse epiglycanin, a mucin expressed on mammary carcinoma TA3-Ha cells but not TA3-St cells, was identified by homology search to a mouse epiglycanin cDNA fragment identified by representational difference analysis between TA3-Ha and TA3-St cells. The open reading frame of this gene was cloned from human cervical carcinoma ME-180 cells. It consists of a mucin domain with 28 nonidentical tandem repeats of 45 nucleotides each corresponding to a threonine/serine-rich peptide, a stem domain, a transmembrane domain, and a cytoplasmic tail. The cloned cDNA with a FLAG sequence was expressed in K562 cells. A combination of immunoprecipitation with a polyclonal antibody specific for the cytoplasmic tail and Western blotting analysis with an anti-FLAG antibody and lectins revealed a mucin-like component as the gene product. Analysis by the use of tissue cDNA libraries indicated that the gene is expressed in lung, large intestine, thymus, and testis among 16 normal tissues tested. The polyclonal antibody specific for a synthetic peptide from the cytoplasmic tail, when tested for its reactivity with normal lung tissues, reacted with epithelia of bronchi and bronchioli but not with alveoli. All of 24 lung adenocarcinomas specimens tested were reactive with the antibody, whereas reactivity was observed with only 2 out of 24 squamous and none out of 24 small cell lung carcinomas. This is a novel transmembrane mucin and designated as MUC21.