title: The ribosomal RNA gene promoter and adjacent cis-acting DNA sequences govern plasmid DNA partitioning and stable inheritance in the parasitic protozoan Leishmania.
abstract: Detailed analysis of the Leishmania donovani ribosomal RNA (rRNA) gene promoter region has allowed the identification of cis-acting sequences involved in plasmid DNA partitioning and stable plasmid inheritance. We report that plasmids bearing the 350 bp rRNA promoter along with the 200 bp region immediately 3' to the promoter exhibited a 6.5-fold increase in transformation frequency and were transmitted to daughter cells as single-copy molecules. This is in contrast to what has been observed for plasmid molecules in this organism so far. Moreover, we show that these low-copy-number plasmids displayed a remarkable mitotic stability in the absence of selective pressure. The region in the vicinity of the RNA pol I transcription initiation site, and also in the adjacent 200 nt, displays a complex structural organization and shares sequence similarity to the yeast autonomously replicating consensus sequence and centromere DNA elements. Deletion analyses indicated that these elements were necessary but not sufficient for plasmid DNA partitioning and stable inheritance, and that the rRNA promoter region was required for optimal function. These results suggest an interplay between RNA pol I transcription, DNA replication, DNA partitioning and mitotic stability in trypanosomatids. This is the first example of defined DNA elements for plasmid partitioning and stable inheritance in the protozoan parasite Leishmania.
authors.affiliation: Infectious Disease Research Center, CHUL Research Center, Faculty of Medicine, Laval University, Quebec, Canada.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boucher
authors.forename: François
authors.initials: F
authors.lastname: McNicoll
authors.forename: Maxime
authors.initials: M
authors.lastname: Laverdière
authors.forename: Annie
authors.initials: A
authors.lastname: Rochette
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Chou
authors.forename: Barbara
authors.initials: B
authors.lastname: Papadopoulou
mesh_terms: D000818:Animals; D001483:Base Sequence; D002455:Cell Division; D002478:Cells, Cultured; D020090:Chromosome Segregation; D004261:DNA Replication; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics*; D007893:Leishmania donovani / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D008938:Mitosis / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012318:RNA Polymerase I / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics; D014170:Transformation, Genetic
chemical_list: D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D012319:RNA Polymerase II; D012318:RNA Polymerase I