Presland R B, Gregg K, Molloy P L, Morris C P, Crocker L A, Rogers G E
Department of Biochemistry, University of Adelaide, South Australia.
J Mol Biol. 1989 Oct 20;209(4):549-59. doi: 10.1016/0022-2836(89)90593-7.
The nucleotide sequence of the four complete chicken feather keratin genes A to D contained in the previously isolated recombinant lambda CFK1 has been determined. All four genes have a very similar structure; each gene encodes a polypeptide of 97 amino acid residues and contains an intron in the 5' non-coding region, 37 base-pairs from the cap site. Comparison of the previously determined feather keratin gene C sequence to genes A, B and D indicates that a high level of gene correction has occurred in the protein coding and 5' non-coding regions, which show more than 90% homology, whereas the intron and 3' non-coding regions are by contrast poorly conserved with one or two exceptions. The dramatic conservation of the 5' non-coding region between the feather keratin sequences and an unrelated but co-expressed gene encoding a histidine-rich protein suggests that this segment may play an important role in transcriptional regulation. In addition, both gene types contain an identically positioned intron in the 5' non-coding region. Northern blots performed using gene-specific probes show that the four characterized genes A to D plus gene E, which is partially contained in the recombinant lambda CFK1, are all expressed in feather tissue from 14-day old chick embryos. In addition, we report that a scale keratin gene (originally isolated from a scale complementary DNA library) is expressed at a low level in the embryonic feather.
已确定先前分离的重组λCFK1中包含的四个完整鸡羽毛角蛋白基因A至D的核苷酸序列。所有四个基因都具有非常相似的结构；每个基因编码一个由97个氨基酸残基组成的多肽，并在5'非编码区含有一个内含子，距帽位点37个碱基对。将先前确定的羽毛角蛋白基因C序列与基因A、B和D进行比较表明，在蛋白质编码区和5'非编码区发生了高水平的基因校正，这些区域显示出超过90%的同源性，而内含子和3'非编码区则相反，除一两个例外，保守性很差。羽毛角蛋白序列与一个无关但共表达的富含组氨酸蛋白的基因之间5'非编码区的显著保守性表明，该片段可能在转录调控中起重要作用。此外，两种基因类型在5'非编码区都含有一个位置相同的内含子。使用基因特异性探针进行的Northern印迹显示，四个已表征的基因A至D以及部分包含在重组λCFK1中的基因E，都在14日龄鸡胚的羽毛组织中表达。此外，我们报告称，一个鳞片角蛋白基因（最初从鳞片互补DNA文库中分离）在胚胎羽毛中低水平表达。
