Sequence of cDNA coding for human keratin 19.
Sequence of cDNA coding for human keratin 19.
复制标题
编码人角蛋白 19 的 cDNA 序列。
作者：
Pauline C. Stasiak;E. B. Lane
我们利用特异性单克隆抗体从人胎盘lambda gtll表达文库中分离克隆，获得了人角蛋白19 （40kD;(1)）的cDNA序列。该序列有一个全长的开放阅读框（起始ATG和停止密码子下划线）。虽然角蛋白19被认为是简单上皮的特征，但其序列明显更接近于人类角化细胞角蛋白（2,3），而不是简单上皮角蛋白18(4)。它与同源牛角蛋白非常相似(5)：在3'非翻译区有73%的碱基相同，在编码区，头部结构域有86%的同源性，螺旋杆结构域有89.5%的同源性。在短尾域（pos’s）。1168-1207)，这一比例降至64%，尽管其他角蛋白在这三个结构域中与同源蛋白在物种边界上保持80%以上的一致性。该序列的翻译表明，在氨基酸水平上，尾部同源性甚至更低（38%:13个氨基酸中只有5个共享）。人类和牛在尾部区域序列上的高度差异表明，这个区域几乎没有受到任何选择压力的影响。这表明角蛋白19异常短的尾巴，就像我们自己的一样，是退化的。
We present the cDNA sequence of human keratin 19 (40kD;(1)) determined from clones isolated from a lambda gtll expression library of human placenta by using specific monoclonal antibodies . The sequence has a full-length open reading frame (initiating ATG and stop codon are underlined). Although keratin 19 is considered characteristic of simple epithelia, the sequence is clearly closer to human keratinocyte keratins (2,3) than to the simple epithelial keratin 18 (4). It is very similar to that of the homologous bovine keratin (5): 73% bases are identical in the 3' untranslated region, and in the coding region there is 86% identity over the head domain and 89.5% over the helical rod domain. In the short tail domain (pos'ns. 1168-1207) this falls to only 64%, even though other keratins maintain over 80% identity with homologous proteins across species boundaries in all three domains. Translation of this sequence shows the tail homology to be even lower at the amino acid level (38%: only 5 out of the 13 amino acids shared). This high divergence between human and bovine sequences over the tail domain suggests that little if any selection pressure has been acting on this region. This indicates that the abnornally short tail of keratin 19 is, like our own, vestigial.