Structure of the two related elastase genes expressed in the rat pancreas.
Structure of the two related elastase genes expressed in the rat pancreas.
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发表时间：
1984-11
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通讯作者：
G. Swift;C. Craik;S. Stary;C. Quinto;R. Lahaie;W. Rutter;Raymond J MacDonald
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作者：
G. Swift;C. Craik;S. Stary;C. Quinto;R. Lahaie;W. Rutter;Raymond J MacDonald
我们分离并鉴定了带有两种在外分泌胰腺中表达的分泌性弹性蛋白酶基因的大鼠基因组 DNA 片段。报告了每个基因的完整外显子序列以及相当多的内含子和侧翼序列。每个弹性蛋白酶基因都被位于两个基因内相应位置的七个插入序列打断，但有一个例外：弹性蛋白酶 II 基因的第三个内含子已在 5' 方向移动了一个密码子。氨基酸编码结构域内内含子的放置部分可以反映通过编码包含三个β折叠的特征性多肽结构的外显子的复制而形成祖丝氨酸蛋白酶基因。酶原的激活肽和信号肽在蛋白质前体中形成离散的功能域，由单独的外显子编码。除了 TATAA 盒外，这两个基因在 5' 端侧翼区域（上游最多约 450 个碱基对）具有相当大的序列相似性；然而，必须引入许多缺口来优化序列比对。相似性主要限于序列保守性超过 70% 的 6 个寡核苷酸区域。弹性蛋白酶 I 基因具有完美重复共聚物 (GT)24，位于转录起点上游 427-379 个核苷酸处。弹性蛋白酶 II 基因在上游 384-330 个核苷酸处具有类似的富含 GT 的区域（52/55 G 或 T）。将两个弹性蛋白酶基因的 5' 侧翼区域与胰凝乳蛋白酶以及胰蛋白酶 I 和 II 的 5' 侧翼区域进行比较表明，六个保守寡核苷酸区域之一通常对于这些基因也是保守的。该保守区域包含推定的增强子核心序列。
We have isolated and characterized rat genomic DNA fragments bearing the two secretory elastase genes that are expressed in the exocrine pancreas. The complete exonic sequences for each of the genes as well as considerable intronic and flanking sequences are reported. Each elastase gene is interrupted by seven intervening sequences which are located at corresponding positions within the two genes, with one exception: the third intron of the elastase II gene has shifted one codon in the 5' direction. The placement of introns within the amino acid coding domains in part may reflect the formation of the progenitor serine protease gene by the duplication of an exon encoding a characteristic polypeptide structure comprising three beta sheets. The activation peptides of the zymogens and the signal peptides, which form discrete functional domains in the protein precursors, are encoded by separate exons. In addition to the TATAA box, the two genes share considerable sequence similarity in the 5'-proximal flanking regions (up to approximately 450 base pairs upstream); however, a number of gaps must be introduced to optimize the sequence alignment. The similarities are largely confined to six oligonucleotide regions with greater than 70% sequence conservation. The elastase I gene has a perfect repeating copolymer (GT)24 located 427-379 nucleotides upstream from the start of transcription. The elastase II gene has a similar GT-rich region (52/55 G or T) located 384-330 nucleotides upstream. Comparison of the 5'-flanking regions of the two elastase genes with those of pancreatic chymotrypsin and trypsin I and II reveals that one of the six conserved oligonucleotide regions is generally conserved for these genes as well. This conserved region contains putative enhancer core sequences.