Qian F, Frankfater A, Chan S J, Steiner D F
Department of Biochemistry and Molecular Biology, University of Chicago, IL 60637.
DNA Cell Biol. 1991 Apr;10(3):159-68. doi: 10.1089/dna.1991.10.159.
The mouse cathepsin B gene and its flanking regions were cloned and characterized. The gene contains 10 exons and 9 introns spanning about 20 kb. Although the exon-intron organization of the mouse cathepsin B gene showed some similarity to the rat cathepsin H and L genes, significant differences were found. In particular, the highly conserved sequence that contains the catalytically active cysteine in these genes is split at different sites by an intron. As with other thiol proteinases, there is no obvious correspondence between the coding exons and structural or functional units within preprocathepsin B. These results suggest that the lysosomal thiol proteinase genes are evolutionarily ancient and that intron shifting has occurred subsequent to their divergence from a common ancestral form. The 5'-flanking region and exon 1 sequences in the mouse cathepsin B gene have a high GC content of approximately 72%. The 5'-flanking region also contains several potential Sp1 binding sites, but lacks TATA and CAAT motifs. These characteristics suggest that cathepsin B is a "housekeeping" gene and its transcription may be controlled by multiple transcription factors, including Sp1.
克隆并鉴定了小鼠组织蛋白酶B基因及其侧翼区域。该基因包含10个外显子和9个内含子，跨度约为20 kb。尽管小鼠组织蛋白酶B基因的外显子-内含子结构与大鼠组织蛋白酶H和L基因有一些相似之处，但也发现了显著差异。特别是，这些基因中包含催化活性半胱氨酸的高度保守序列被一个内含子在不同位点分开。与其他巯基蛋白酶一样，前组织蛋白酶B中的编码外显子与结构或功能单元之间没有明显的对应关系。这些结果表明，溶酶体巯基蛋白酶基因在进化上很古老，并且在它们从共同的祖先形式分化之后发生了内含子移位。小鼠组织蛋白酶B基因的5'侧翼区域和外显子1序列的GC含量很高，约为72%。5'侧翼区域还包含几个潜在的Sp1结合位点，但缺乏TATA和CAAT基序。这些特征表明组织蛋白酶B是一个“管家”基因，其转录可能受多种转录因子控制，包括Sp1。
