title: Intronic hammerhead ribozymes are ultraconserved in the human genome.
abstract: Small ribozymes have been regarded as living fossils of a prebiotic RNA world that would have remained in the genomes of modern organisms. In this study, we report the ultraconserved occurrence of hammerhead ribozymes in Amniota genomes (reptiles, birds and mammals, including humans), similar to those described previously in amphibians and platyhelminth parasites. The ribozymes mapped to intronic regions of different genes, such as the tumour suppressor RECK in birds and mammals, a mammalian tumour antigen and the dystrobrevin beta in lizards and birds. In vitro characterization confirmed a high self-cleavage activity, whereas analysis of RECK-expressed sequence tags revealed fusion events between the in vivo self-cleaved intron and U5 or U6 small nuclear RNA fragments. Together, these results suggest a conserved role for these ribozymes in messenger RNA biogenesis.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Cientificas, Avenida de los Naranjos s/n, 46022 Valencia, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: de la Peña
authors.forename: Inmaculada
authors.initials: I
authors.lastname: García-Robles
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics; D001483:Base Sequence; D019295:Computational Biology; D019143:Evolution, Molecular; D016147:Genes, Tumor Suppressor; D015894:Genome, Human; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016337:RNA, Catalytic / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D000951:Antigens, Neoplasm; D016337:RNA, Catalytic; C427204:hammerhead ribozyme