RRC ID 19820
著者 Inagaki Y, Ehara M, Watanabe KI, Hayashi-Ishimaru Y, Ohama T.
タイトル Directionally evolving genetic code: the UGA codon from stop to tryptophan in mitochondria.
ジャーナル J Mol Evol
Abstract For the comprehensive analyses of deviant codes in protistan mitochondria (mt), we sequenced about a 1.1-kb region of a mitochondrial (mt) gene, the cytochrome c oxidase subunit I (coxI) in two chlorarachniophytes, the filose amoeba Euglypha rotunda, the cryptomonad Cryptomonas ovata, the prymnesiophyte (haptophyte) Diacronema vlkianum (Pavlovales), and the diatom Melosira ambigua. As a result of this analysis, we noticed that the UGA codon is assigned to tryptophan (Trp) instead of being a signal for translational termination in two chlorarachniophytes and in E. rotunda. The same type of deviant code was reported previously in animals, fungi, ciliates, kinetoplastids, Chondrus crispus (a red alga), Acanthamoeba castellanii (an amoeboid protozoon), and three of the four prymnesiophyte orders with the exception of the Pavlovales. A phylogenetic analysis based on the COXI sequences of 56 eukaryotes indicated that the organisms bearing the modified code, UGA for Trp, are not monophyletic. Based on these studies, we propose that the ancestral mitochondrion was bearing the universal genetic code and subsequently reassigned the codon to Trp independently, at least in the lineage of ciliates, kinetoplastids, rhodophytes, prymnesiophytes, and fungi. We also discuss how this codon was directionally captured by Trp tRNA.
巻・号 47(4)
ページ 378-84
公開日 1998-10-1
DOI 10.1007/pl00006395
PMID 9767683
MeSH Amoeba / enzymology Amoeba / genetics* Animals Base Sequence Codon / genetics* Codon, Terminator / genetics* DNA Primers DNA, Mitochondrial / genetics* Electron Transport Complex IV / genetics* Eukaryota / enzymology Eukaryota / genetics* Evolution, Molecular* Genetic Code* Macromolecular Substances Mitochondria / enzymology Phylogeny* Polymerase Chain Reaction / methods Tryptophan*
IF 1.821
引用数 29
WOS 分野 GENETICS & HEREDITY BIOCHEMISTRY & MOLECULAR BIOLOGY EVOLUTIONARY BIOLOGY
リソース情報
藻類 NIES-12 NIES-227 NIES-274