EMA2 is required for target-directed scnRNA degradation.
Ontology highlight
ABSTRACT:
ORGANISM(S): Tetrahymena thermophila
PROVIDER: GSE243435 | GEO | 2023/09/18
REPOSITORIES: GEO
Similar Datasets
Project description:Small RNAs target their complementary chromatin regions for gene silencing through nascent long non-coding RNAs (lncRNAs). In programmed DNA elimination of the ciliated protozoan Tetrahymena, the interaction between Piwi-associated small RNA (scnRNAs) and the lncRNA transcripts from the somatic genome has been proposed to induce target-directed scnRNA degradation (TDSD) and scnRNAs not targeted for TDSD later target the germline-limited sequences for DNA elimination. In this study, we show that the SUMO E3 ligase Ema2 is required for the accumulation of lncRNAs from somatic genome, and thus for TDSD and completing DNA elimination to make viable sexual progeny. Ema2 interacts with the SUMO E2 conjugating enzyme Ubc9 and enhances SUMOylation of the transcription regulator Spt6. We further show that Ema2 promotes the association of Spt6 and RNA polymerase II to chromatin. These results suggest that Ema2-directed SUMOylation actively promotes the lncRNA transcription that is a prerequisite for communication between the genome and small RNAs.
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Project description:In the ciliated protozoan Tetrahymena, an RNAi-mediated feedback loop is important for assembling heterochromatin on the sequences that are removed from the somatic genome by programmed DNA elimination. Because heterochromatin is formed exclusively on the eliminated sequences, some mechanism must inhibit this feedback loop at the boundaries of the eliminated sequences. In this study, we show that the HP1-like protein Coi6p, its interaction partners Coi7p and Lia5p, and the histone demethylase Jmj1p are crucial for confining the production of small RNAs to the eliminated sequences.
2017-03-06 | GSE87011 | GEO
Project description:In the ciliated protozoan Tetrahymena, de novo heterochromatin body formation is accompanied by programmed DNA elimination. We previously reported that dephosphorylation of the HP1-like protein Pdd1p is required for the formation of heterochromatin bodies during the process of programmed DNA elimination in the ciliated protozoan Tetrahymena. Here, we show that the heterochromatin body component Jub4p is required for Pdd1p phosphorylation, heterochromatin body formation and DNA elimination. Moreover, our analyses of unphosphorylatable Pdd1p mutants demonstrate that Pdd1p phosphorylation is required for heterochromatin body formation and DNA elimination, while it is dispensable for local heterochromatin assembly. Therefore, both phosphorylation and the following dephosphorylation of Pdd1p are necessary to facilitate the formation of heterochromatin bodies. We suggest that Jub4p-mediated phosphorylation of Pdd1p creates a chromatin environment that is a prerequisite for subsequent heterochromatin body assembly and DNA elimination. 26 to 32-nt small RNAs from various mutants were analyzed by high-throughput sequencing
2016-07-15 | E-GEOD-83250 | biostudies-arrayexpress
Project description:Microarray analyses were performed to compare the gene expression profiles of wild-type and several mutant strains of the ciliated protozoan Tetrahymena thermophila. Elimination of H3K4 methylation (hht2-K4Q) and knockout of either of the ubiquitylation enzymes (delta-UBC2 and delta-BRE1) affects a broader spectrum of genes than elimination of H2B ubiquitylation (htb1-K115R). Cells at mid-logarithmic growing phase (cell density of 200,000 cells/ml) were collected. Then total RNAs were extracted and hybridized.
2010-06-20 | E-GEOD-18743 | biostudies-arrayexpress
Project description:In the ciliated protozoan Tetrahymena, de novo heterochromatin body formation is accompanied by programmed DNA elimination. We previously reported that dephosphorylation of the HP1-like protein Pdd1p is required for the formation of heterochromatin bodies during the process of programmed DNA elimination in the ciliated protozoan Tetrahymena. Here, we show that the heterochromatin body component Jub4p is required for Pdd1p phosphorylation, heterochromatin body formation and DNA elimination. Moreover, our analyses of unphosphorylatable Pdd1p mutants demonstrate that Pdd1p phosphorylation is required for heterochromatin body formation and DNA elimination, while it is dispensable for local heterochromatin assembly. Therefore, both phosphorylation and the following dephosphorylation of Pdd1p are necessary to facilitate the formation of heterochromatin bodies. We suggest that Jub4p-mediated phosphorylation of Pdd1p creates a chromatin environment that is a prerequisite for subsequent heterochromatin body assembly and DNA elimination. New macronuclei (MACs) of exconjugants were isolated from wild-type and various mutant cells at 12 hpm (hours post-mixing), sheared chromatin was immunoprecipitated andprecipitated DNA was analyzed by high-throughput sequencing
2016-07-15 | E-GEOD-83249 | biostudies-arrayexpress
Project description:In the ciliated protozoan Tetrahymena, de novo heterochromatin body formation is accompanied by programmed DNA elimination. We previously reported that dephosphorylation of the HP1-like protein Pdd1p is required for the formation of heterochromatin bodies during the process of programmed DNA elimination in the ciliated protozoan Tetrahymena. Here, we show that the heterochromatin body component Jub4p is required for Pdd1p phosphorylation, heterochromatin body formation and DNA elimination. Moreover, our analyses of unphosphorylatable Pdd1p mutants demonstrate that Pdd1p phosphorylation is required for heterochromatin body formation and DNA elimination, while it is dispensable for local heterochromatin assembly. Therefore, both phosphorylation and the following dephosphorylation of Pdd1p are necessary to facilitate the formation of heterochromatin bodies. We suggest that Jub4p-mediated phosphorylation of Pdd1p creates a chromatin environment that is a prerequisite for subsequent heterochromatin body assembly and DNA elimination.
2016-07-15 | GSE83250 | GEO
Project description:In the ciliated protozoan Tetrahymena, de novo heterochromatin body formation is accompanied by programmed DNA elimination. We previously reported that dephosphorylation of the HP1-like protein Pdd1p is required for the formation of heterochromatin bodies during the process of programmed DNA elimination in the ciliated protozoan Tetrahymena. Here, we show that the heterochromatin body component Jub4p is required for Pdd1p phosphorylation, heterochromatin body formation and DNA elimination. Moreover, our analyses of unphosphorylatable Pdd1p mutants demonstrate that Pdd1p phosphorylation is required for heterochromatin body formation and DNA elimination, while it is dispensable for local heterochromatin assembly. Therefore, both phosphorylation and the following dephosphorylation of Pdd1p are necessary to facilitate the formation of heterochromatin bodies. We suggest that Jub4p-mediated phosphorylation of Pdd1p creates a chromatin environment that is a prerequisite for subsequent heterochromatin body assembly and DNA elimination.
2016-07-15 | GSE83249 | GEO
Project description:The ciliated protozoan Tetrahymena undergoes extensive programmed DNA elimination when the germline micronucleus produces the new macronucleus during sexual reproduction. DNA elimination is epigenetically controlled by DNA sequences of the parental macronuclear genome, and this epigenetic regulation is mediated by small RNAs (scnRNAs) of approximately 28-30 nucleotides that are produced and function by an RNAi-related mechanism. Here, we examine scnRNA production and turnover by deep sequencing. scnRNAs are produced exclusively from the micronucleus and non-homogeneously from a variety of chromosomal locations. scnRNAs are preferentially derived from the eliminated sequences, and this preference is mainly determined at the level of transcription. Despite this bias, a significant fraction of scnRNAs is also derived from the macronuclear-destined sequences, and these scnRNAs are degraded during the course of sexual reproduction. These results indicate that the pattern of DNA elimination in the new macronucleus is shaped by the biased transcription in the micronucleus and by the selective degradation of scnRNAs in the parental macronucleus. GRO-Seq and Examination of siRNAs in wild-type,nullisomic 4, EMA1 KO, and TWI1 KO Tetrahymena cells
2012-06-21 | E-GEOD-38768 | biostudies-arrayexpress
Project description:Microarray analyses were performed to compare the gene expression profiles of wild-type and several mutant strains of the ciliated protozoan Tetrahymena thermophila. Elimination of H3K4 methylation (hht2-K4Q) and knockout of either of the ubiquitylation enzymes (delta-UBC2 and delta-BRE1) affects a broader spectrum of genes than elimination of H2B ubiquitylation (htb1-K115R).
2009-10-27 | GSE18743 | GEO
Project description:Heterochromatic histone H3 methylation at lysine 9 (H3K9me2/3) and lysine 27 (H3K27me3) is generally catalyzed by SUV39 and EZH family methyltransferases, respectively, and has distinct functions in most eukaryotes. In contrast, the ciliated protozoan Tetrahymena lacks the SUV39 enzyme, and the EZH enzyme Ezl1p is responsible for the deposition of both H3K9me3 and H3K27me3 during Piwi-directed DNA elimination. Understanding how both modifications are catalyzed by the EZH enzyme should shed light on the mechanism and the evolution of the division of labor between the two heterochromatic histone methyltransferase families in eukaryotes. Here, we show that loss of the novel protein Ded2p abolishes the accumulation of H3K9me3 but not H3K27me3 in Tetrahymena. The phenotypes of DED2 KO cells revealed that H3K27me3 is sufficient for promoting secondary small RNA biogenesis but not for suppressing TEs, assembling heterochromatin bodies and completing DNA elimination. Ded2p associates with Ezl1p through Rnf2p, a component of Tetrahymena Polycomb Repressive Complex 2 (PRC2) to promote the accumulation of H3K9me3. Our results indicate that there are functional distinctions between H3K9me3 and H3K27me3 in different steps of the DNA elimination process and the specificity of the methyltransferase activity of PRC2 can be modulated by its associated factor to catalyze H3K9me3.
2023-04-01 | GSE190308 | GEO