title: A meiosis-specific Spt5 homolog involved in non-coding transcription.
abstract: Spt5 is a conserved and essential transcriptional regulator that binds directly to RNA polymerase and is involved in transcription elongation, polymerase pausing and various co-transcriptional processes. To investigate the role of Spt5 in non-coding transcription, we used the unicellular model Paramecium tetraurelia. In this ciliate, development is controlled by epigenetic mechanisms that use different classes of non-coding RNAs to target DNA elimination. We identified two SPT5 genes. One (STP5v) is involved in vegetative growth, while the other (SPT5m) is essential for sexual reproduction. We focused our study on SPT5m, expressed at meiosis and associated with germline nuclei during sexual processes. Upon Spt5m depletion, we observed absence of scnRNAs, piRNA-like 25 nt small RNAs produced at meiosis. The scnRNAs are a temporal copy of the germline genome and play a key role in programming DNA elimination. Moreover, Spt5m depletion abolishes elimination of all germline-limited sequences, including sequences whose excision was previously shown to be scnRNA-independent. This suggests that in addition to scnRNA production, Spt5 is involved in setting some as yet uncharacterized epigenetic information at meiosis. Our study establishes that Spt5m is crucial for developmental genome rearrangements and necessary for scnRNA production.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland.
authors.forename: Julita
authors.initials: J
authors.lastname: Gruchota
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, University of Paris Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Denby Wilkes
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, University of Paris Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Arnaiz
authors.affiliation: Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, University of Paris Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Linda
authors.initials: L
authors.lastname: Sperling
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland.
authors.forename: Jacek K
authors.initials: JK
authors.lastname: Nowak
mesh_terms: D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation / Q000235:genetics; D015321:Gene Rearrangement / Q000235:genetics; D016678:Genome; D008540:Meiosis / Q000235:genetics*; D016805:Paramecium tetraurelia / Q000235:genetics; D012098:Reproduction / Q000235:genetics*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000235:genetics*
chemical_list: D035602:Transcriptional Elongation Factors