LOCALIZATION AND DIFFERENTIAL EXPRESSION OF 2 ISOFORMS OF THE TIGHT JUNCTION PROTEIN ZO-1
LOCALIZATION AND DIFFERENTIAL EXPRESSION OF 2 ISOFORMS OF THE TIGHT JUNCTION PROTEIN ZO-1
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DOI：
10.1152/ajpcell.1992.262.5.c1119
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发表时间：
1992-05-01
影响因子：
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通讯作者：
ANDERSON, JM
中科院分区：
文献类型：
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作者：
WILLOTT, E;BALDA, MS;ANDERSON, JM
ZO-1 是一种大约 225 kDa 的外周膜蛋白，位于所有紧密连接的细胞质侧。 ZO-1 cDNA 测序显示，仅在部分研究的 ZO-1 cDNA 中存在 240 bp 序列。 这个 240 bp 的区域编码了 80 个氨基酸的框内插入，称为基序-α。 通过 RNA 逆转录和 DNA 扩增显示了正常大鼠和人体组织以及人上皮细胞系（Caco-2、T84、Hep G2）中预测转录物的表达。 免疫印迹分析显示两种蛋白质亚型都存在；然而，在不同的细胞系中，它们的数量彼此之间存在显着差异。 使用针对基序α或其侧翼共享序列产生的抗体，在光和超微结构水平上进行免疫定位，表明两种形式无法区分地定位于紧密连接。 这些观察结果证明了 ZO-1 同工型的存在和可变表达，并提出了这些同工型是否有助于不同上皮细胞中紧密连接多样性的问题。
ZO-1 is a peripheral membrane protein of approximately 225 kDa located on the cytoplasmic side of all tight junctions. ZO-1 cDNA sequencing disclosed the presence of a 240-bp sequence in only some of the ZO-1 cDNAs studied. This 240-bp region encoded an inframe insertion of 80 amino acids, named motif-alpha. Expression of the predicted transcripts in normal rat and human tissues and in human epithelial cell lines (Caco-2, T84, Hep G2) was shown by reverse transcription of RNA and then DNA amplification. Immunoblot analysis showed both protein isoforms were present; however, in different cell lines, their amounts differed markedly relative to each other. Immunolocalization at light and ultrastructural levels, using antibodies generated against motif-alpha or shared sequences flanking it, indicated both forms localized indistinguishably to tight junctions. These observations demonstrate the existence and variable expression of ZO-1 isoforms and raise the question whether these isoforms contribute to tight junction diversity in different epithelia.