title: Paramecium tetraurelia chromatin assembly factor-1-like protein PtCAF-1 is involved in RNA-mediated control of DNA elimination.
abstract: Genome-wide DNA remodelling in the ciliate Paramecium is ensured by RNA-mediated trans-nuclear crosstalk between the germline and the somatic genomes during sexual development. The rearrangements include elimination of transposable elements, minisatellites and tens of thousands non-coding elements called internally eliminated sequences (IESs). The trans-nuclear genome comparison process employs a distinct class of germline small RNAs (scnRNAs) that are compared against the parental somatic genome to select the germline-specific subset of scnRNAs that subsequently target DNA elimination in the progeny genome. Only a handful of proteins involved in this process have been identified so far and the mechanism of DNA targeting is unknown. Here we describe chromatin assembly factor-1-like protein (PtCAF-1), which we show is required for the survival of sexual progeny and localizes first in the parental and later in the newly developing macronucleus. Gene silencing shows that PtCAF-1 is required for the elimination of transposable elements and a subset of IESs. PTCAF-1 depletion also impairs the selection of germline-specific scnRNAs during development. We identify specific histone modifications appearing during Paramecium development which are strongly reduced in PTCAF-1 depleted cells. Our results demonstrate the importance of PtCAF-1 for the epigenetic trans-nuclear cross-talk mechanism.
authors.affiliation: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland Graduate School for Cellular and Biomedical Sciences, University of Bern, Freiestrasse 1, 3012 Bern, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Ignarski
authors.affiliation: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland Graduate School for Cellular and Biomedical Sciences, University of Bern, Freiestrasse 1, 3012 Bern, Switzerland.
authors.forename: Aditi
authors.initials: A
authors.lastname: Singh
authors.affiliation: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland.
authors.forename: Estienne C
authors.initials: EC
authors.lastname: Swart
authors.affiliation: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland Graduate School for Cellular and Biomedical Sciences, University of Bern, Freiestrasse 1, 3012 Bern, Switzerland.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Arambasic
authors.affiliation: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland.
authors.forename: Pamela Y
authors.initials: PY
authors.lastname: Sandoval
authors.affiliation: Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland mariusz.nowacki@izb.unibe.ch.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Nowacki
mesh_terms: D002470:Cell Survival; D056504:Chromatin Assembly Factor-1 / Q000378:metabolism / Q000502:physiology*; D016054:DNA, Protozoan / Q000378:metabolism*; D044127:Epigenesis, Genetic; D006657:Histones / Q000378:metabolism; D048648:Macronucleus / Q000378:metabolism; D016805:Paramecium tetraurelia / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015800:Protozoan Proteins / Q000378:metabolism / Q000502:physiology*; D016053:RNA, Protozoan / Q000378:metabolism*; D058727:RNA, Small Untranslated / Q000378:metabolism*; D012098:Reproduction
chemical_list: D056504:Chromatin Assembly Factor-1; D016054:DNA, Protozoan; D006657:Histones; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D058727:RNA, Small Untranslated