A novel mitochondrial protein, Tar1p, is encoded on the antisense strand of the nuclear 25S rDNA
A novel mitochondrial protein, Tar1p, is encoded on the antisense strand of the nuclear 25S rDNA
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DOI：
10.1101/gad.1035002
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发表时间：
2002-11-01
影响因子：
10.5
通讯作者：
Snyder, M
中科院分区：
文献类型：
--
作者：
Coelho, PSR;Bryan, AC;Snyder, M
在真核生物中，人们普遍认为编码蛋白质和结构RNA的基因不重叠。使用转座子标记策略来全局分析酿酒酵母基因组中表达的基因，我们在染色体XII上的核rDNA重复区中的25 S rRNA基因中完全包含并转录反义的开放阅读框中鉴定了多个插入。该基因TAR 1（核糖体RNA反义转录物）的表达可以在RNA和蛋白质水平上检测到，并且相应的124个氨基酸蛋白质的一级序列在几种酵母物种中是保守的。Tar1p被发现定位于线粒体，并且该蛋白的过表达抑制线粒体RNA聚合酶中的点突变的呼吸缺陷型，该点突变影响线粒体基因表达和mtDNA稳定性。这些发现表明，蛋白质和结构RNA的编码信息可以重叠，提出了关于这些复杂基因的共同进化的问题，也表明rDNA转录和线粒体功能在真核细胞中受到协调调节。
In eukaryotes, it is widely assumed that genes coding for proteins and structural RNAs do not overlap. Using a transposon-tagging strategy to globally analyze the Saccharomyces cerevisiae genome for expressed genes, we identified multiple insertions in an open reading frame that is contained fully within and transcribed antisense to the 25S rRNA gene in the nuclear rDNA repeat region on Chromosome XII. Expression of this gene, TAR1 (Transcript Antisense to Ribosomal RNA), can be detected at the RNA and protein levels, and the primary sequence of the corresponding 124-amino-acid protein is conserved in several yeast species. Tar1p was found to localize to mitochondria, and overexpression of the protein suppresses the respiration-deficient petite phenotype of a point mutation in mitochondrial RNA polymerase that affects mitochondrial gene expression and mtDNA stability. These findings indicate that coding information for protein and structural RNAs can overlap, raising issues regarding the coevolution of such complex genes, and also suggest that rDNA transcription and mitochondrial function are coordinately regulated in eukaryotic cells.