title: Cloning and characterization of ribosomal RNA genes from Opisthorchis viverrini.
abstract: The ribosomal DNA (rDNA) unit of the liver fluke Opisthorchis viverrini has been cloned and characterized. The results demonstrated that the total length of this unit is approximately 13 kb, containing 4.2 kb of large subunit (LSU) rDNA, 2.0 kb of small subunit (SSU) rDNA, 1.0 kb of transcribed spacer DNA and 5.8 kb of non-transcribed + external transcribed spacer DNA. Examination of the non-transcribed spacer region between different rDNA units showed variation in the restriction sites rather than in the length. Judging from hybridization of the rDNA plasmid to the restriction endonuclease digest of genomic DNA, rDNA units represent 6.1% of the total genomic DNA. At the RNA level, the LSU rRNA of O. viverrini and Fasciola gigantica contained a hidden break. The molecule consisted of two fragments co-migrating with a SSU rRNA, when electrophoresis was carried out under denaturing conditions. Ribosomal RNA sequence comparison has been previously used to determine phylogenetic classification of parasitic organisms. The sequence of 381 nucleotides at the 5' terminus of the LSU rRNA gene was determined and compared with those from species previously reported by other investigators. Phylogenetic classification of O. viverrini, as determined by rRNA gene sequence comparison, is comparable with the conventional taxonomic classification.
authors.affiliation: Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Korbsrisate
authors.forename: S
authors.initials: S
authors.lastname: Mongkolsuk
authors.forename: J R
authors.initials: JR
authors.lastname: Haynes
authors.forename: Q
authors.initials: Q
authors.lastname: Wong
authors.forename: S
authors.initials: S
authors.lastname: Sirisinha
mesh_terms: D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004275:DNA, Ribosomal / Q000737:chemistry*; D015723:Gene Library; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009891:Opisthorchis / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics*; D015183:Restriction Mapping
chemical_list: D004275:DNA, Ribosomal; D012335:RNA, Ribosomal