Phylogenetic position of the mitochondrion-lacking protozoan Trichomonas tenax, based on amino acid sequences of elongation factors 1alpha and 2.
Major parts of amino-acid-coding regions of elongation factor (EF)-1alpha and EF-2 in Trichomonas tenax were amplified by PCR from total genomic DNA and the products were cloned into a plasmid vector, pGEM-T. The three clones from each of the products of the EF-1alpha and EF-2 were isolated and sequenced. The insert DNAs of the clones containing EF-1alpha coding regions were each 1,185 bp long with the same nucleotide sequence and contained 53.1% of G + C nucleotides. Those of the clones containing EF-2 coding regions had two different sequences; one was 2,283 bp long and the other was 2,286 bp long, and their G + C contents were 52.5 and 52.9%, respectively. The copy numbers of the EF-1alpha and EF-2 gene per chromosome were estimated as four and two, respectively. The deduced amino acid sequences obtained by the conceptual translation were 395 residues from EF-1alpha and 761 and 762 residues from the EF-2s. The sequences were aligned with the other eukaryotic and archaebacterial EF-1alphas and EF-2s, respectively. The phylogenetic position of T. tenax was inferred by the maximum likelihood (ML) method using the EF-1alpha and EF-2 data sets. The EF-1alpha analysis suggested that three mitochondrion-lacking protozoa, Glugea plecoglossi, Giardia lamblia, and T. tenax, respectively, diverge in this order in the very early phase of eukaryotic evolution. The EF-2 analysis also supported the divergence of T. tenax to be immediately next to G. lamblia.
Yamamoto
A
A
Department of Oral Microbiology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142, Japan. ayamamot@dent.showa-u.ac.jp
Hashimoto
T
T
Asaga
E
E
Hasegawa
M
M
Goto
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001482:Base Composition; D005075:Biological Evolution; D003001:Cloning, Molecular; D018628:Gene Dosage; D017125:Genes, Protozoan / Q000235:genetics; D008928:Mitochondria; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000235:genetics*; D010802:Phylogeny; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014244:Trichomonas / Q000235:genetics*
D020648:Peptide Elongation Factor 1; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors