title: Sir2a regulates rDNA transcription and multiplication rate in the human malaria parasite Plasmodium falciparum.
abstract: The Plasmodium falciparum histone deacetylase Sir2a localizes at telomeric regions where it contributes to epigenetic silencing of clonally variant virulence genes. Apart from telomeres, PfSir2a also accumulates in the nucleolus, which harbours the developmentally regulated ribosomal RNA genes. Here we investigate the nucleolar function of PfSir2a and demonstrate that PfSir2a fine-tunes ribosomal RNA gene transcription. Using a parasite line in which PfSir2a has been disrupted, we observe that histones near the transcription start sites of all ribosomal RNA genes are hyperacetylated and that transcription of ribosomal RNA genes is upregulated. Complementation of the PfSir2a-disrupted parasites restores the ribosomal RNA levels, whereas PfSir2a overexpression in wild-type parasites decreases ribosomal RNA synthesis. Furthermore, we observe that PfSir2a modulation of ribosomal RNA synthesis is linked to an altered number of daughter merozoites and the parasite multiplication rate. These findings provide new insights into an epigenetic mechanism that controls malaria parasite proliferation and virulence.
authors: Département de Parasitologie et Mycologie, Institut Pasteur, Unité de Biologie des Interactions Hôte-Parasite, F-75724 Paris, France.
authors: Liliana
authors: L
authors: Mancio-Silva
authors: Jose Juan
authors: JJ
authors: Lopez-Rubio
authors: Aurélie
authors: A
authors: Claes
authors: Artur
authors: A
authors: Scherf
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004275:DNA, Ribosomal / Q000235:genetics*; D004912:Erythrocytes / Q000469:parasitology; D005816:Genetic Complementation Test; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D052940:Merozoites / Q000166:cytology / Q000254:growth & development / Q000648:ultrastructure; D009154:Mutation / Q000235:genetics; D010271:Parasites / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D010957:Plasmids / Q000378:metabolism; D010963:Plasmodium falciparum / Q000166:cytology / Q000235:genetics* / Q000254:growth & development* / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004275:DNA, Ribosomal; D015800:Protozoan Proteins