title: Highly divergent actins from karyorelictean, heterotrich, and litostome ciliates.
abstract: We have cloned, sequenced, and characterized cDNA of actins from five ciliate species of three different classes of the phylum Ciliophora: Karyorelictea (Loxodes striatus), Heterotrichea (Blepharisma japonicum, Blepharisma musculus), and Litostomatea (Didinium nasutum, Dileptus margaritifer). Loxodes striatus uses UGA as the stop codon and has numerous in-frame UAA and UAG, which are translated into glutamine. The other four species use UAA as the stop codon and have no in-frame UAG nor UGA. The putative amino acid sequences of the newly determined actin genes were found to be highly divergent as expected from previous findings of other ciliate actins. These sequences were also highly divergent from other ciliate actins, indicating that actin genes are highly diverse even within the phylum Ciliophora. Phylogenetic analysis showed high evolutionary rate of ciliate actins. Our results suggest that the evolutionary rate was accelerated because of the differences in molecular interactions.
authors.affiliation: The Division of Human Environmental Sciences, Graduate School of Human Culture, Nara Women's University, Kitauoyanishi-machi, Nara 630-8506, Japan.
authors.forename: Oanh T P
authors.initials: OT
authors.lastname: Kim
authors.forename: Kei
authors.initials: K
authors.lastname: Yura
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Go
authors.forename: Terue
authors.initials: T
authors.lastname: Harumoto
mesh_terms: D000199:Actins / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D016798:Ciliophora / Q000737:chemistry / Q000235:genetics*; D018388:Codon, Terminator; D018076:DNA, Complementary; D005815:Genetic Code; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics; D016053:RNA, Protozoan / Q000302:isolation & purification; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D000199:Actins; D018388:Codon, Terminator; D018076:DNA, Complementary; D015800:Protozoan Proteins; D016053:RNA, Protozoan