ORGANIZATION AND SEQUENCE OF THE HUMAN GENE ENCODING CYTOKERATIN-8
ORGANIZATION AND SEQUENCE OF THE HUMAN GENE ENCODING CYTOKERATIN-8
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DOI：
10.1016/0378-1119(90)90285-y
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发表时间：
1990-02-14
期刊：
影响因子：
3.5
通讯作者：
FRANKE, WW
中科院分区：
文献类型：
--
作者：
KRAUSS, S;FRANKE, WW
在各种中间丝(IF)蛋白中，细胞角蛋白8(CK8)尤其引人注目，因为它是在胚胎发育早期产生的，是许多简单上皮细胞中唯一存在的II型CK，也可以在某些非上皮细胞中合成。利用针对人CK8的cDNA探针，我们分离到了一个约为CK8的基因。14kb的基因组克隆(在噬菌体EMBL3中)，它包含编码人CK8的基因。该基因共包含7766个核苷酸(NT)，从转录起始点(通过引物延伸分析确定)到聚腺苷酸化位点(通过cDNA测序确定)，以及1030-NT 5‘’上游区域已经被测序。由外显子序列推导出的485个氨基酸(Aa)序列(Mr 53 532)与牛、鼠和两栖动物的相应基因产物具有很强的同源性。令人惊讶的是，CK8基因只有7个内含子，而不是在同一(II型)CK亚家族的所有其他基因中发现的8个内含子；虽然所有7个内含子都出现在与其他II型CK编码基因相同的位置，但这些基因的内含子V在CK8基因中缺失。CK8的内含子I非常长(2534个核苷酸)，包含一组潜在的调控序列，包括三个Sp1位点和一个扩展的Alu元件。在Southern-Blot分析中，我们发现在人类基因组中只有一个编码CK8的内含子基因，通过异源转染实验，我们证明该基因在表达该同源基因的非人类细胞中正确转录。CK8基因的分离和鉴定为研究其染色体环境和表达调控原理提供了必要的基础。
Among the various intermediate filament (IF) proteins, cytokeratin 8 (CK8) is especially remarkable as it is produced early in embryogenesis, is the only type-II CK occurring in many simple epithelial cells, and can also be synthesized in certain non-epithelial cells. Using a cDNA probe specific for human CK8 we have isolated an approx. 14-kb genomic clone (in phage .lambda.EMBL3) which contains the gene encoding human CK8. The gene comprising a total of 7766 nucleotides (nt) from the transcription start point, determined by primer extension analysis, to the polyadenylation site, determined from cDNA sequencing, and a 1030-nt 5'' upstream region have been sequenced. The sequence of 485 amino acids (aa) deduced from the exon sequences (Mr 53 532) shows strong homology with the corresponding gene products of bovine, murine and amphibian (Xenopus laevis) origins. Suprisingly, the ck8 gene contains only seven introns instead of eight as found in all other genes of the same (type-II) CK subfamily; while all seven introns occur in identical positions as in the other type-II CK-encoding genes, intron V of these genes is missing in the ck8 gene. Intron I of ck8 is remarkably long (2534 nt) and contains a cluster of potential regulatory sequences, including three Sp1 sites, and an extended Alu-element. In Southern-blot analyses, we found only one intron-containing gene encoding CK8 in the human genome, and by heterologous transfection experiments we showed that this gene is correctly transcribed in non-human cells expressing the orthologous gene. The isolation and characterization of the ck8 gene provide the necessary basis for studying its chromosomal environment and the principles of regulation of its expression.