Identification of the mitochondrial targeting signal of yeast glutamyl-tRNA synthetase

• Main Authors: Nien-tzu Chen, 陳念慈
• Other Authors: Chien-chia Wang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/72264724593825241374

碩士 === 國立中央大學 === 生命科學研究所 === 98 === In Saccharomyces cerevisiae, the cytoplasmic glutamyl-tRNA synthetase (cGluRS) is encoded by GUS1. In cytoplasm, cGluRS attaches Glu to the cognate tRNAGlu to form Glu-tRNAGlu. In addition to the cytoplasmic activity, cGluRS can enter the mitochodria to synthesize Glu-tNRAGln (a misacylated product), which is then converted to correct Gln-tRNAGln by Glu-tNRAGln amidotransferase. A pervious study in our lab indicated that Arc1p, which binds cGluRS in cytoplasm, also has a mitochondrial targeting signal. Our results showed that cGluRS and Arc1p each carry a mitochondrial targeting signal and thus can enter the mitochondria by itself. Next, we used the cytoplasmic form of valyl-tRNA synthetase as the reporter gene to map the mitochondrial targeting signal of cGluRS. As it turned out, this signal was embedded in the N-terminal amino acids 1-29 of cGluRS. In contrast, no mitochondrial targeting signal was found in Schizosaccharomyces pombe or Candida albicans GluRS. Moreover, Arc1p from Pichia guilliermodii, Candida albicans, and Schizosaccharomyces pombe does not possess a mitochondrial targeting signal.