Low level expression of cytokeratins 8, 18 and 19 in vascular smooth muscle cells of human umbilical cord and in cultured cells derived therefrom, with an analysis of the chromosomal locus containing the cytokeratin 19 gene.
Low level expression of cytokeratins 8, 18 and 19 in vascular smooth muscle cells of human umbilical cord and in cultured cells derived therefrom, with an analysis of the chromosomal locus containing the cytokeratin 19 gene.
复制标题
细胞角蛋白 8、18 和 19 在人脐带血管平滑肌细胞及其衍生培养细胞中的低水平表达，并对含有细胞角蛋白 19 基因的染色体基因座进行分析。
DOI：
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发表时间：
1988
影响因子：
6.6
通讯作者：
W. Franke
中科院分区：
文献类型：
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作者：
B. Bader;L. Jahn;W. Franke
在各种中间丝（IF）蛋白中，某些细胞角蛋白，通常是上皮分化的标志，也可以在一些非上皮细胞中检测到少量。我们研究了这种非典型表达的一个代表性的情况下，平滑肌细胞的血管壁的人脐带，在蛋白质和核酸水平上，通过光镜和电镜免疫定位，凝胶电泳和免疫印迹的细胞骨架蛋白，和mRNA鉴定北方印迹。对于后者，我们已经使用了敏感的探针为各种细胞角蛋白，包括新的探针为细胞角蛋白19。我们还描述了17号染色体的基因座，包括细胞角蛋白15和19的基因，我们强调的发生在细胞角蛋白19基因的内含子中的几个不寻常的和进化上稳定的序列元件。大多数，也许是所有这些血管的平滑肌细胞，通过结蛋白和平滑肌型α-肌动蛋白的存在被阳性鉴定，通过细胞角蛋白8和18特异性抗体免疫染色，并且亚群还含有细胞角蛋白19。免疫电子显微镜表明，这些细胞角蛋白被安排在IFs的分布不同，从大多数的IFs形成的结蛋白和波形蛋白。从显微切割的血管壁组织的细胞骨架蛋白的凝胶电泳显示，存在于这些组织中的细胞角蛋白8和18的量是非常低的，占不到总IF蛋白的1%，并且细胞角蛋白19仅以痕量存在。相应地，这些组织中细胞角蛋白8、18和19的mRNA含量远低于平行检查的上皮细胞中存在的mRNA含量。我们还建立了来源于脐带血管平滑肌的细胞培养物，其保持了细胞角蛋白8、18和19以及波形蛋白和平滑肌型α-肌动蛋白的表达，但不合成结蛋白。在这些细胞培养物中，细胞角蛋白以比原始组织中高得多的量存在，并形成IF，令人惊讶的是，IF显示出与波形蛋白IF相似的分布，并且在用秋水仙胺处理细胞时，塌陷成无核聚集体，通常甚至比波形蛋白IF更有效。我们的结论是，在平滑肌细胞的某一亚型中，编码"简单上皮型"细胞角蛋白的基因，即，细胞角蛋白8、18和19表达，并且这些基因的低水平表达与肌源性分化相容。（400字处截断摘要）
Of the various intermediate filament (IF) proteins certain cytokeratins, usually a hallmark of epithelial differentiation, can also be detected in some non-epithelial cells in low amounts. We have studied a representative case of this atypical expression, the smooth muscle cells of the blood vessel walls of the human umbilical cord, at the protein and nucleic acid level, by light and electron microscopic immunolocalization, gel electrophoresis and immunoblotting of cytoskeletal proteins, and mRNA identification by Northern blotting. For the latter we have used sensitive probes for various cytokeratins, including new probes for cytokeratin 19. We also describe the chromosome 17 locus comprising the genes for cytokeratins 15 and 19, and we emphasize the occurrence of several unusual and evolutionarily stable sequence elements in the introns of the cytokeratin 19 gene. Most, perhaps all smooth muscle cells of these blood vessels, positively identified by the presence of desmin and smooth muscle type alpha-actin, are immunostained by antibodies specific for cytokeratins 8 and 18, and a subpopulation also contains cytokeratin 19. Immunoelectron microscopy indicates that these cytokeratins are arranged in IFs that are distributed differently from the majority of the IFs formed by desmin and vimentin. Gel electrophoresis of cytoskeletal proteins from microdissected vascular wall tissue shows that the amounts of cytokeratins 8 and 18 present in these tissues are very low, representing less than 1% of the total IF protein, and that cytokeratin 19 is present only in trace amounts. Correspondingly, the contents of mRNAs for cytokeratins 8, 18 and 19 in these tissues are much lower than those present in epithelial cells examined in parallel. We have also established cell cultures derived from umbilical cord vascular smooth muscles that have maintained the expression of cytokeratins 8, 18 and 19, together with vimentin and the smooth muscle type alpha-actin, but do not synthesize desmin. In these cell cultures the cytokeratins are present in much higher amounts than in the original tissue and form IFs that, surprisingly, show a similar distribution as the vimentin IFs and, upon treatment of the cells with colcemid, collapse into juxtanuclear aggregates, often even more effectively than the vimentin IFs do. We conclude that in a certain subtype of smooth muscle cells, the genes encoding cytokeratins of the "simple epithelial type", i.e., cytokeratins 8, 18 and 19, are expressed and that the low level expression of these genes is compatible with myogenic differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)