Structures, Expression and their Desorders of the Genes for Mitochondrial Proteins

1.克隆了大鼠线粒体鸟氨酸氨甲酰基转移酶（EC 2.1.3.3）基因，该基因位于X染色体上，在肝脏和小肠中特异表达，并测定了其结构。该基因长75个碱基，分为10个外显子。内含子的范围从85个碱基到26个碱基。外显子总数为1.5个，仅占基因的2%，这是迄今报道的基因中最低的值之一。第一个外显子编码大部分NH 2-末端前序列，其作为线粒体靶向信号发挥作用。推定的结合位点的两个底物的酶，氨甲酰磷酸和鸟氨酸，分别由外显子3和9编码。一组“CAAT”和“ATA”盒样序列存在于mRNA 5'端上游200个碱基的位置周围。在这组推定的启动子元件下游约35个碱基处，mRNA的5'端周围的11个核苷酸序列作为直接重复出现。上游 ...更多信息 在mRNA的5'端上游或下游有几个值得注意的序列，它们类似于Sp1结合位点、增强子核心序列、糖皮质激素受体结合位点的共有序列和在肝脏中特异性表达的另一种基因的推定增强子元件。与大多数线粒体基质蛋白不同，大鼠线粒体3-氧代酰基-CoA硫解酶的合成没有短暂的前序列，并具有线粒体靶向和输入成熟蛋白的信息。两个重叠的cDNA克隆含有一个开放阅读框，编码397个氨基酸残基的多肽（预测Mr=41868），5'端非翻译区164个碱基对，3'端非翻译区264个碱基对和poly（A）区。线粒体硫解酶的氨基酸序列与大鼠过氧化物酶体3-氧代酰基- CoA硫解酶前体的成熟部分的氨基酸序列有37%相同。这些结果表明，这两个硫解酶有一个共同的起源，并在进化过程中获得的信息，针对各自的细胞器。线粒体硫解酶中的两个序列可以作为线粒体靶向信号。少

1. The rat mitochondrial ornithine carbamoyltransferase (EC 2.1.3.3) gene located on the X chromosome and expressed specifically in the liver and small intestine was cloned and the structure determined. This gene is 75 kilobases long and is split into ten exons. The introns range from 85 bases to 26 kilobases. The sum of the total exons is 1.5 kilobases and occupies only 2% of the gene; this value being one of the lowest among genes heretofore reported. The first exon encodes most of the NH2- Terminal presequence which functions as a mitochondrial targeting signal. Putative binding sites for the two substrates of the enzyme, carbamoyl phosphate and ornithine, are encoded by exon 3 and 9, respectively. A set of "CAAT" and "ATA" box-like sequences is present around the position 200 bases upstream from the 5' end of the mRNA. About 35 bases downstream from this set of putative promoter elements, an 11-nucleotide sequence around the 5' end of the mRNA reappears, as a direct repeat. Upstrea … More m or downstream from the 5' end of the mRNA there are several noteworthy sequences which resemble the Sp1-binding site, the enhancer core sequence, the consensus sequence for the glucocorticoid receptor binding sites, and the putative enhancer element of another gane which is expressed specifically in the liver.2. Unlike most mitochondrial matrix proteins, mitochondrial 3-oxoacyl-CoA thiolase in rats is synthesized with no transient presequence and possesses information for mitochondrial targeting and import in the mature protein. Two overlapping cDNA clones contained an open reading frame encoking a polypeptide of 397 amino acid residues (predicted Mr=41868), 5' untranslated sequence of 164 base pairs, 3' untranslated sequence of 264 base pairs and poly(A) tract. The amino acid sequence of the mitochondrial thiolase is 37% identical with that of the mature portion of rat peroxisomal 3-oxoacyl- CoA thiolase precursor. These results suggest that the two thiolases have a common origin and obtained information for targeting to respective organelles during evolution. Two sequences in the mitochondrial thiolase that may serve as a mitochondrial targeting signal are presented. Less