Phylogenetic affinity of mitochondria of Euglena gracilis and kinetoplastids using cytochrome oxidase I and hsp60

• Published in: Journal of molecular evolution Vol. 44; no. 3; pp. 341 - 347
• Main Authors: Yasuhira, S. (Tohoku University, Sendai, Japan.), Simpson, L
• Format: Journal Article
• Language: English
• Published: Germany Springer Nature B.V 01.03.1997
• Subjects: ADN; Animals; Chaperonin 60 - genetics; Cloning, Molecular; CODE GENETIQUE; CODIGO GENETICO; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; Cytochrome; DNA, Mitochondrial; Electron Transport Complex IV - genetics; ESTRES TERMICO; Euglena gracilis; Euglena gracilis - genetics; Evolutionary biology; Freshwater; GENE; GENES; Kinetoplastida - genetics; MASTIGOPHORA; Mitochondria - enzymology; Mitochondria - metabolism; Mitochondrial DNA; MITOCHONDRIE; MITOCONDRIA; Molecular Sequence Data; OXIDORREDUCTASAS; OXYDOREDUCTASE; Phylogenetics; Phylogeny; Plastids; PROTEINAS; PROTEINE; PROTOZOA; Ribonucleic acid; RNA; SECUENCIA NUCLEOTIDICA; SEQUENCE NUCLEOTIDIQUE; STRESS THERMIQUE
• ISSN: 0022-2844; 1432-1432
• DOI: 10.1007/PL00006152

The mitochondrial DNA-encoded cytochrome oxidase subunit I (COI) gene and the nuclear DNA-encoded hsp60 gene from the euglenoid protozoan Euglena gracilis were cloned and sequenced. The COI sequence represents the first example of a mitochondrial genome-encoded gene from this organism. This gene contains seven TGG tryptophan codons and no TGA tryptophan codons, suggesting the use of the universal genetic code. This differs from the situation in the mitochondrion of the related kinetoplastid protozoa, in which TGA codes for tryptophan. In addition, a complete absence of CGN triplets may imply the lack of the corresponding tRNA species. COI cDNAs from E. gracilis possess short 5' and 3' untranslated transcribed sequences and lack a 3' poly[A] tail. The COI gene does not require uridine insertion/deletion RNA editing, as occurs in kinetoplastid mitochondria, to be functional, and no short guide RNA-like molecules could be visualized by labeling total mitochondrial RNA with [alpha-32P]GTP and guanylyl transferase. In spite of the differences in codon usage and the 3' end structures of mRNAs, phylogenetic analysis using the COI and hsp60 protein sequences suggests a monophyletic relationship between the mitochondrial genomes of E. gracilis and of the kinetoplastids, which is consistent with the phylogenetic relationship of these groups previously obtained using nuclear ribosomal RNA sequences