KTF-1, a transcriptional activator of Xenopus embryonic keratin expression.
KTF-1, a transcriptional activator of Xenopus embryonic keratin expression.
复制标题
KTF-1，非洲爪蟾胚胎角蛋白表达的转录激活剂。
作者：
A. Snape;E. Jónás;T. Sargent
非洲爪蟾胚胎的核提取物含有一种蛋白质活性 KTF-1，它在体外与胚胎表皮特异性角蛋白基因 XK81A1 的启动子结合。迁移率测定、甲基化干扰和足迹分析用于表明 KTF-1 结合位点包含不完美的回文序列 ACCCTGAGGCT。该序列在 XK81A1 启动子中出现一次，位于转录起始位点上游 152-162 个碱基对处。角蛋白基因的序列被改变，使其在体外不再与 KTF-1 结合，在注射到非洲爪蟾胚胎后，转录水平严重降低，但保留了表皮特异性。添加 KTF-1 结合位点还增强了异源启动子（非洲爪蟾 β-珠蛋白）在胚胎中的表皮和非表皮活性。这些结果表明，KTF-1 是胚胎角蛋白转录的通用激活剂，它与其他因子协同作用，产生高水平的表皮特异性表达。
Nuclear extracts from embryos of Xenopus laevis were shown to contain a protein activity, KTF-1, which binds in vitro to the promoter of the embryonic, epidermis-specific keratin gene, XK81A1. Mobility shift assays, methylation interference and footprinting analysis were used to show that the KTF-1 binding site contains an imperfect, palindromic sequence, ACCCTGAGGCT. This sequence occurs once in the XK81A1 promoter, 152-162 base pairs upstream of the transcription start site. A construct of the keratin gene in which this sequence was altered so that it no longer binds KTF-1 in vitro showed severely reduced transcription levels upon injection into Xenopus embryos, but retained epidermal specificity. Addition of KTF-1 binding sites also enhanced epidermal and non-epidermal activity of a heterologous promoter, Xenopus beta-globin, in embryos. These results suggest that KTF-1 is a general activator of embryonic keratin transcription, which acts in concert with other factors to produce high levels of epidermis-specific expression.