title: Homology-dependent gene silencing in Paramecium.
abstract: Microinjection at high copy number of plasmids containing only the coding region of a gene into the Paramecium somatic macronucleus led to a marked reduction in the expression of the corresponding endogenous gene(s). The silencing effect, which is stably maintained throughout vegetative growth, has been observed for all Paramecium genes examined so far: a single-copy gene (ND7), as well as members of multigene families (centrin genes and trichocyst matrix protein genes) in which all closely related paralogous genes appeared to be affected. This phenomenon may be related to posttranscriptional gene silencing in transgenic plants and quelling in Neurospora and allows the efficient creation of specific mutant phenotypes thus providing a potentially powerful tool to study gene function in Paramecium. For the two multigene families that encode proteins that coassemble to build up complex subcellular structures the analysis presented herein provides the first experimental evidence that the members of these gene families are not functionally redundant.
authors.affiliation: Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France.
authors.forename: F
authors.initials: F
authors.lastname: Ruiz
authors.forename: L
authors.initials: L
authors.lastname: Vayssié
authors.forename: C
authors.initials: C
authors.lastname: Klotz
authors.forename: L
authors.initials: L
authors.lastname: Sperling
authors.forename: L
authors.initials: L
authors.lastname: Madeddu
mesh_terms: D000818:Animals; D002923:Cilia / Q000737:chemistry; D005089:Exocytosis; D018628:Gene Dosage; D005786:Gene Expression Regulation; D017125:Genes, Protozoan; D008565:Membrane Proteins / Q000235:genetics; D008845:Microinjections; D009154:Mutation; D010247:Paramecium / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D010957:Plasmids; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: C099867:ICL1a protein, Paramecium tetraurelia; D008565:Membrane Proteins; C107339:ND7 protein, Protozoa; D015800:Protozoan Proteins