title: Dynamic distributions of long double-stranded RNA in Tetrahymena during nuclear development and genome rearrangements.
abstract: Bi-directional non-coding transcripts and their ∼29-nt small RNA products are known to guide DNA deletion in Tetrahymena, leading to the removal of one-third of the genome from developing somatic nuclei. Using an antibody specific for long double-stranded RNAs (dsRNAs), we determined the dynamic subcellular distributions of these RNAs. Conjugation-specific dsRNAs were found and show sequential appearances in parental germline, parental somatic nuclei and finally in new somatic nuclei of progeny. The dsRNAs in germline nuclei and new somatic nuclei are likely transcribed from the sequences destined for deletion; however, the dsRNAs in parental somatic nuclei are unexpected, and PCR analyses suggested that they were transcribed in this nucleus. Deficiency in the RNA interference (RNAi) pathway led to abnormal aggregations of dsRNA in both the parental and new somatic nuclei, whereas accumulation of dsRNAs in the germline nuclei was only seen in the Dicer-like gene mutant. In addition, RNAi mutants displayed an early loss of dsRNAs from developing somatic nuclei. Thus, long dsRNAs are made in multiple nuclear compartments and some are linked to small RNA production whereas others might participate in their regulations.
authors.affiliation: Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Tai-Ting
authors.initials: TT
authors.lastname: Woo
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Ju-Lan
authors.initials: JL
authors.lastname: Chao
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan mcyao@gate.sinica.edu.tw.
authors.forename: Meng-Chao
authors.initials: MC
authors.lastname: Yao
mesh_terms: D002467:Cell Nucleus / Q000502:physiology*; D015321:Gene Rearrangement; D018503:Genome, Protozoan; D006570:Heterochromatin / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D034443:RNA Transport; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism*; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism*; D013768:Tetrahymena
chemical_list: D006570:Heterochromatin; D015800:Protozoan Proteins; D012330:RNA, Double-Stranded; D016053:RNA, Protozoan
keywords: Ciliates; Genome rearrangements; Heterochromatin; RNAi; dsRNA