title: Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an 'intron' bearing a hidden break site.
abstract: Splitting and apparent splicing of ribosomal RNA, both previously unknown in vertebrates, were found in rodents of the genus Ctenomys. Instead of being formed by a single molecule of 4.4 kb, 28S rRNA is split in two molecules of 2.6 and 1.8 kb. A hidden break, mapping within a 106 bp 'intron' located in the D6 divergent region, is expressed in mature ribosomes of liver, lung, heart and spleen, as well as in primary fibroblast cultures. Testis-specific processing eliminates the intron and concomitantly the break site, producing non-split 28S rRNA molecules exclusively in this organ. The intron is flanked by two 9 bp direct repeats, revealing the acquisition by insertion of a novel rRNA processing strategy in the evolution of higher organisms.
authors.affiliation: Laboratorio de Fisiología y Biología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, (1428) Buenos Aires, Argentina.
authors.forename: G J
authors.initials: GJ
authors.lastname: Melen
authors.forename: C G
authors.initials: CG
authors.lastname: Pesce
authors.forename: M S
authors.initials: MS
authors.lastname: Rossi
authors.forename: A R
authors.initials: AR
authors.lastname: Kornblihtt
mesh_terms: D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D019143:Evolution, Molecular; D007438:Introns / Q000235:genetics*; D008297:Male; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D009928:Organ Specificity; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics*; D012339:RNA, Ribosomal, 28S / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D012377:Rodentia / Q000235:genetics; D013737:Testis / Q000166:cytology / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D012322:RNA Precursors; D012339:RNA, Ribosomal, 28S