A team of heterochromatin factors collaborates with small RNA pathways to combat repetitive elements and germline stress
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA345009 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR4319290.fastq.gz | Fastqsanger.gz | |||
| SRR4319300.fastq.gz | Fastqsanger.gz | |||
| SRR4319310.fastq.gz | Fastqsanger.gz | |||
| SRR4319281.fastq.gz | Fastqsanger.gz | |||
| SRR4319291.fastq.gz | Fastqsanger.gz |
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Project description:Repetitive sequences derived from transposons make up a large fraction of eukaryotic genomes and must be silenced to protect genome integrity. Repetitive elements are often found in heterochromatin; however, the roles and interactions of heterochromatin proteins in repeat regulation are poorly understood. Here we show that a diverse set of C. elegans heterochromatin proteins act together with the piRNA and nuclear RNAi pathways to silence repetitive elements and prevent genotoxic stress in the germ line. Mutants in genes encoding HPL-2/HP1, LIN-13, LIN-61, LET-418/Mi-2, and H3K9me2 histone methyltransferase MET-2/SETDB1 also show functionally redundant sterility, increased germline apoptosis, DNA repair defects, and interactions with small RNA pathways. Remarkably, fertility of heterochromatin mutants could be partially restored by inhibiting cep-1/p53, endogenous meiotic double strand breaks, or the expression of MIRAGE1 DNA transposons. Functional redundancy among these factors and pathways underlies the importance of safeguarding the genome through multiple means.
2017-03-11 | GSE87523 | GEO
Project description:Repetitive sequences derived from transposons make up a large fraction of eukaryotic genomes and must be silenced to protect genome integrity. Repetitive elements are often found in heterochromatin; however, the roles and interactions of heterochromatin proteins in repeat regulation are poorly understood. Here we show that a diverse set of C. elegans heterochromatin proteins act together with the piRNA and nuclear RNAi pathways to silence repetitive elements and prevent genotoxic stress in the germ line. Mutants in genes encoding HPL-2/HP1, LIN-13, LIN-61, LET-418/Mi-2, and H3K9me2 histone methyltransferase MET-2/SETDB1 also show functionally redundant sterility, increased germline apoptosis, DNA repair defects, and interactions with small RNA pathways. Remarkably, fertility of heterochromatin mutants could be partially restored by inhibiting cep-1/p53, endogenous meiotic double strand breaks, or the expression of MIRAGE1 DNA transposons. Functional redundancy among these factors and pathways underlies the importance of safeguarding the genome through multiple means.
2017-03-11 | GSE87522 | GEO
Project description:Repetitive sequences derived from transposons make up a large fraction of eukaryotic genomes and must be silenced to protect genome integrity. Repetitive elements are often found in heterochromatin; however, the roles and interactions of heterochromatin proteins in repeat regulation are poorly understood. Here we show that a diverse set of C. elegans heterochromatin proteins act together with the piRNA and nuclear RNAi pathways to silence repetitive elements and prevent genotoxic stress in the germ line. Mutants in genes encoding HPL-2/HP1, LIN-13, LIN-61, LET-418/Mi-2, and H3K9me2 histone methyltransferase MET-2/SETDB1 also show functionally redundant sterility, increased germline apoptosis, DNA repair defects, and interactions with small RNA pathways. Remarkably, fertility of heterochromatin mutants could be partially restored by inhibiting cep-1/p53, endogenous meiotic double strand breaks, or the expression of MIRAGE1 DNA transposons. Functional redundancy among factors and pathways underlies the importance of safeguarding the genome through multiple means.
| S-EPMC5395297 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2017-03-11 | GSE87524 | GEO
Project description:A team of heterochromatin factors collaborates with small RNA pathways to combat repetitive elements and germline stress [RNA-seq]
| PRJNA345014 | ENA
Project description:A team of heterochromatin factors collaborates with small RNA pathways to combat repetitive elements and germline stress [ChIP-seq]
| PRJNA345015 | ENA
Project description:The assembly of repressive heterochromatin domains in eukaryotic genomes is crucial for silencing lineage-inappropriate genes and repetitive DNA elements. Paradoxically, transcription of repetitive elements within constitutive heterochromatin domains is required for RNA-based mechanisms, such as the RNAi pathway, to target heterochromatin assembly proteins. However, the mechanism by which heterochromatic repeat elements are transcribed has been unclear. Using fission yeast, we show that the conserved trimeric transcription factor (TF) PhpCNF-Y complex, which includes histone fold domain proteins, can infiltrate constitutive heterochromatin to transcribe repeat elements. PhpCNF-Y collaborates with a Zn-finger containing TF to bind heterochromatic repeat promoter regions with CCAAT boxes. Mutating either the TFs or the CCAAT binding site disrupts the transcription of heterochromatic repeats. Although repeat elements are transcribed from both strands, PhpCNF-Y-dependent transcripts originate from only one strand. These TF-driven transcripts contain cryptic introns that are processed via a mechanism requiring the spliceosome to generate small interfering RNAs (siRNAs) by the RNAi machinery. Our analyses show that siRNA production by this TF-mediated transcription pathway is critical for nucleation of heterochromatin at target repeat loci. This study reveals a mechanism by which heterochromatic repeats are transcribed, initiating their own silencing by triggering a primary cascade that produces siRNAs necessary for heterochromatin nucleation.
2024-06-21 | MSV000095108 | MassIVE
Project description:Many repetitive DNA elements are packaged in heterochromatin, but depend on occasional transcription to maintain long-term silencing. The factors that promote transcription of repeat elements in heterochromatin are largely unknown. Here, we show that DOT1L, a histone methyltransferase that modifies lysine 79 of histone H3 (H3K79), is required for transcription of major satellite repeats to maintain pericentromeric heterochromatin (PCH), and that this function is essential for preimplantation development. DOT1L is a transcriptional activator at single-copy genes but does not have a known role in repeat element transcription. We show that H3K79me3 is specifically enriched at repetitive elements, that loss of DOT1L compromises pericentromeric major satellite transcription, and that this function depends on interaction between DOT1L and the chromatin remodeler SMARCA5. DOT1L inhibition causes chromosome breaks and cell cycle defects, and leads to embryonic lethality. Together, our findings uncover a vital new role for DOT1L in transcriptional activation of heterochromatic repeats.
2023-05-26 | PXD028824 | Pride
Project description:Heterochromatin, typically marked by H3K9me3 or H3K27me3, is key to the repression of genes and repetitive elements. The mechanisms responsible for establishing and maintaining heterochromatin in a locus specific manner are unclear. Heterochromatin restricts cell identity by preventing activation of alternative lineage genes. This barrier can be partially overcome by inducing ectopic transcription factors (TFs) to activate an alternative transcriptional program. However, TFs are impeded by highly restrictive heterochromatin leading to low reprogramming rates and incomplete activation of the target transcriptome. Previously we utilized the heterochromatin property of sonication resistance to identify 172 proteins associated with sonication resistant heterochromatin (srHC) by mass spectrometry (Becker, et al., 2017). We hypothesized that by functionally assessing the srHC proteins and identifying the genes they repress during reprogramming we could improve our understanding of heterochromatin maintenance and learn how to disrupt heterochromatin to enhance reprogramming. Focusing on reprogramming from fibroblasts to induced human hepatocytes (hiHeps) we conducted an siRNA screen of 97 srHC proteins without reprogramming factors (noTF) and with hiHep reprogramming and assessed the impact on the expression of genes located in srHC domains by RNA-seq. We identified enhancer of rudimentary homolog (ERH) as a key regulator of H3K9me3 heterochromatin maintenance. ERH was found to associate broadly with H3K9me3 domains and when depleted caused global changes in H3K9me3 and srHC. Collectively our screen of srHC protein repressive function demonstrates specific functionality of groups of srHC proteins and increases our understanding of H3K9me3 gene repression.
2021-06-24 | GSE154232 | GEO
Project description:Heterochromatin, typically marked by H3K9me3 or H3K27me3, is key to the repression of genes and repetitive elements. The mechanisms responsible for establishing and maintaining heterochromatin in a locus specific manner are unclear. Heterochromatin restricts cell identity by preventing activation of alternative lineage genes. This barrier can be partially overcome by inducing ectopic transcription factors (TFs) to activate an alternative transcriptional program. However, TFs are impeded by highly restrictive heterochromatin leading to low reprogramming rates and incomplete activation of the target transcriptome. Previously we utilized the heterochromatin property of sonication resistance to identify 172 proteins associated with sonication resistant heterochromatin (srHC) by mass spectrometry (Becker, et al., 2017). We hypothesized that by functionally assessing the srHC proteins and identifying the genes they repress during reprogramming we could improve our understanding of heterochromatin maintenance and learn how to disrupt heterochromatin to enhance reprogramming. Focusing on reprogramming from fibroblasts to induced human hepatocytes (hiHeps) we conducted an siRNA screen of 97 srHC proteins without reprogramming factors (noTF) and with hiHep reprogramming and assessed the impact on the expression of genes located in srHC domains by RNA-seq. We identified enhancer of rudimentary homolog (ERH) as a key regulator of H3K9me3 heterochromatin maintenance. ERH was found to associate broadly with H3K9me3 domains and when depleted caused global changes in H3K9me3 and srHC. Collectively our screen of srHC protein repressive function demonstrates specific functionality of groups of srHC proteins and increases our understanding of H3K9me3 gene repression.
2021-06-24 | GSE154148 | GEO