Krieg T M, Schafer M P, Cheng C K, Filpula D, Flaherty P, Steinert P M, Roop D R
J Biol Chem. 1985 May 25;260(10):5867-70.
The genomic structure of the mouse 59-kDa keratin gene, a Type I intermediate filament (IF) gene is presented. A comparison of the organization of this gene with that of the human 67-kDa keratin, a Type II IF gene, and hamster vimentin, a Type III IF gene, suggests a common evolutionary origin for Type I, II, and III IF genes. Most introns in these three types of IF genes occur at similar positions within the region encoding sequences predicted to form coiled-coils, but do not delineate structural subdomains. Interestingly though, most of the introns interrupt at or near the beginning of the characteristic 7-residue (heptad) repeat of sequences which form the coiled-coil. These data suggest that the three types of IF genes arose from a common ancestor which may have been assembled from smaller units containing multiple heptad repeats. Subsequent duplication events may then have formed the three known alpha-helical types and each of their various members.
本文介绍了小鼠59-kDa角蛋白基因（一种I型中间丝（IF）基因）的基因组结构。将该基因的组织与人类67-kDa角蛋白基因（一种II型IF基因）以及仓鼠波形蛋白基因（一种III型IF基因）进行比较，结果表明I型、II型和III型IF基因具有共同的进化起源。这三种类型的IF基因中的大多数内含子出现在预测形成卷曲螺旋的编码序列区域内的相似位置，但并未划定结构亚域。然而有趣的是，大多数内含子在形成卷曲螺旋的序列的特征性7个残基（七肽）重复序列的开头或附近中断。这些数据表明，这三种类型的IF基因起源于一个共同的祖先，该祖先可能是由包含多个七肽重复序列的较小单位组装而成。随后的复制事件可能形成了三种已知的α-螺旋类型及其各个成员。
