Fuchs E V, Coppock S M, Green H, Cleveland D W
Cell. 1981 Nov;27(1 Pt 2):75-84. doi: 10.1016/0092-8674(81)90362-7.
Bacterial plasmids containing cDNA sequences specific for keratins were constructed from mRNA of cultured human epidermal cells. Two separate classes of cloned cDNAs were identified by positive hybrid selection: one class removed from total human epidermal mRNA a fraction that was translated into 56 and 58 kilodalton (kd) keratins, and the other class selected mRNAs that translated into a mixture of 50 kd and 46 kd keratins. When probes specific for these two keratin classes were hybridized with human DNA digested with a restriction endonuclease that does not cleave within the probe, two distinct patterns of about ten fragments each were observed. Most of the hybridizing genomic fragments corresponded to complete cDNA sequences, and it is estimated that each of the two classes is encoded by about 10 genes. When the probes were hybridized with DNA from different species, all vertebrates were found to contain discrete sequences homologous to both human keratin probes. Within each vertebrate species, the two probes always hybridized with approximately equal intensities to nonoverlapping sets of genomic sequences, suggesting a coordinate evolution between the two subfamilies of keratin genes. This finding has important functional implications for keratin filament assembly.
从培养的人表皮细胞的mRNA构建了含有角蛋白特异性cDNA序列的细菌质粒。通过阳性杂交筛选鉴定出两类不同的克隆cDNA：一类从总的人表皮mRNA中去除了一部分可被翻译成56和58千道尔顿（kd）角蛋白的片段，另一类筛选出可被翻译成50 kd和46 kd角蛋白混合物的mRNA。当用对这两类角蛋白特异的探针与用一种不在探针内切割的限制性内切酶消化的人DNA杂交时，观察到两种不同的模式，每种模式各有大约十个片段。大多数杂交的基因组片段对应于完整的cDNA序列，据估计这两类角蛋白各自由大约10个基因编码。当探针与来自不同物种的DNA杂交时，发现所有脊椎动物都含有与两种人角蛋白探针同源的离散序列。在每个脊椎动物物种内，两种探针总是以大致相等的强度与不重叠的基因组序列组杂交，这表明角蛋白基因的两个亚家族之间存在协同进化。这一发现对角蛋白丝组装具有重要的功能意义。
