title: RNA-dependent genome processing during nuclear differentiation: the model systems of stichotrichous ciliates.
abstract: We introduce ciliated protozoa, and more specifically the stichotrichous ciliates Oxytricha and Stylonychia, as biological model systems for the analysis of programmed DNA-reorganization processes during nuclear differentiation. These include DNA excision, DNA elimination, reordering of gene segments and specific gene amplification. We show that small nuclear RNAs specify DNA sequences to be excised or retained, but also discuss the need for a RNA template molecule derived from the parental nucleus for these processes. This RNA template guides reordering of gene segments to become functional genes and determines gene copy number in the differentiated nucleus. Since the template is derived from the parental macronucleus, gene reordering and DNA amplification are inherited in a non-Mendelian epigenetic manner.
authors.affiliation: Institute of Cell Biology, Centre for Biomedical Research & Education (ZBAF), Stockumer Str. 10, 58453 Witten, Germany.
authors.forename: Gloria
authors.initials: G
authors.lastname: Fuhrmann
authors.forename: Estienne
authors.initials: E
authors.lastname: Swart
authors.forename: Mariusz
authors.initials: M
authors.lastname: Nowacki
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Lipps
mesh_terms: D002467:Cell Nucleus / Q000235:genetics; D016798:Ciliophora / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics*; D005784:Gene Amplification; D018628:Gene Dosage; D018392:Genomic Imprinting / Q000235:genetics*; D048648:Macronucleus / Q000235:genetics; D008954:Models, Biological; D016813:Oxytricha / Q000235:genetics*; D020537:RNA, Small Nucleolar / Q000235:genetics*
chemical_list: D020537:RNA, Small Nucleolar