Structure of two related rat pancreatic trypsin genes.
Structure of two related rat pancreatic trypsin genes.
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发表时间：
1984-11
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通讯作者：
C. Craik;Q. L. Choo;G. Swift;C. Quinto;Raymond J MacDonald;W. Rutter
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作者：
C. Craik;Q. L. Choo;G. Swift;C. Quinto;Raymond J MacDonald;W. Rutter
用克隆的大鼠胰蛋白酶I和胰蛋白酶II cDNA作为探针，通过杂交和体内重组技术，在大鼠基因组文库中检测到一个约10个胰蛋白酶基因的家族。对含有整个胰蛋白酶I基因和大部分胰蛋白酶II基因的两个单独克隆进行测序。四个内含子将胰蛋白酶I编码序列分开。胰蛋白酶II基因的前三个内含子的位置与胰蛋白酶I基因中的位置相同（第四个内含子不存在于胰蛋白酶II克隆中）。两个基因的编码区有88%的同源性，5 '端非编码区有92%的同源性，而3'端非编码区有66%的同源性。相比之下，可能含有控制基因表达的元件的近端5 '侧翼区域-1至-500总体保守性低于30%，但在该区域中可以识别出约70%同源性的片段。这些序列中的一些与胰凝乳蛋白酶和弹性蛋白酶基因中发现的序列同源。更远端的上游序列（-500至-2500）和间插序列显示没有明显的序列同源性（小于20%）。在胰蛋白酶I基因转录起始上游2.5个碱基处以及胰蛋白酶II基因的第二和第三内含子内发现含有均聚嘌呤/嘧啶重复的独特序列。这两个胰蛋白酶基因与其他丝氨酸蛋白酶基因的核苷酸同源性以及内含子位置的相似性清楚地支持了该基因家族成员之间的进化关系。
A family of approximately 10 trypsin genes was detected in a rat genomic library by hybridization and in vivo recombination techniques using cloned rat pancreatic trypsin I and II cDNAs as probes. Two separate clones containing the entire trypsin I gene and most of the trypsin II gene were sequenced. Four introns split the trypsin I coding sequence. The positions of the first three introns of the trypsin II gene are identical with those in the trypsin I gene (the fourth intron was not present in the trypsin II clone). The coding regions of the two genes are 88% homologous; the 5'-noncoding regions are 92% homologous, whereas the 3'-noncoding regions share 66% identity. In contrast, the proximal 5'-flanking regions from -1 to -500 which may contain the elements controlling gene expression are less than 30% conserved overall, but segments of approximately 70% homology can be discerned in this region. Some of these sequences are homologous to sequences found in the chymotrypsin and elastase genes. More distal upstream sequences (-500 to -2500) and the intervening sequences show no evident sequence homology (less than 20%). Unique sequences containing homopolymeric purine/pyrimidine repeats are found 2.5 kilobases upstream from the start of transcription of the trypsin I gene and within the second and third introns of the trypsin II gene. The nucleotide homologies as well as the similarities of intron positions of the two trypsin genes to those of other serine protease genes clearly support an evolutionary relationship between members of this gene family.