Identification of a novel fungal PRC2 accessory subunit
Ontology highlight
ABSTRACT:
ORGANISM(S): Neurospora crassa
PROVIDER: GSE140787 | GEO | 2020/03/30
REPOSITORIES: GEO
Similar Datasets
Project description:Polycomb Group (PcG) proteins are part of an epigenetic cell memory system that plays essential roles in multicellular development, stem cell biology, X-chromosome inactivation, and cancer. In animals, plants, and many fungi, Polycomb Repressive Complex 2 (PRC2) catalyzes trimethylation of histone H3 lysine 27 (H3K27me3) to assemble transcriptionally repressed facultative heterochromatin. PRC2 is structurally and functionally conserved in the model fungus Neurospora crassa, and recent work in this organism has generated insights into PRC2 control and function. To identify new components of the facultative heterochromatin pathway, we performed a targeted screen of Neurospora deletion strains lacking individual ATP-dependent chromatin remodeling enzymes. We found the Neurospora homolog of IMITATION SWITCH (ISW) is critical for normal transcriptional repression, nucleosome organization, and establishment of typical histone methylation patterns in facultative heterochromatin domains. We also found that stable interaction between PRC2 and chromatin depends on ISW. A functional ISW ATPase domain is required for gene repression and H3K27 methylation. ISW homologs interact with accessory proteins to form multiple complexes with distinct functions. Using proteomics and molecular approaches, we identified three distinct Neurospora ISW-containing complexes. A triple mutant lacking three ISW-accessory factors and disrupting multiple ISW complexes led to widespread upregulation of PRC2 target genes and altered H3K27 methylation patterns, similar to an ISW-deficient strain. Taken together, our data show that ISW is a key component of the facultative heterochromatin pathway in Neurospora and that distinct ISW complexes perform an apparently overlapping role to regulate chromatin structure and gene repression at PRC2 target domains.
2021-01-05 | GSE150758 | GEO
Project description:Identification of a novel fungal PRC2 accessory subunit
| PRJNA590966 | ENA
Project description:Background: Regulation of chromatin accessibility and transcription are tightly coordinated processes. Studies in yeast and higher eukaryotes has described accessible chromatin regions, but little work has been done in filamentous fungi. Results: Here we present a genome-scale characterization of accessible chromatin regions in Neurospora crassa, which revealed characteristic molecular features of accessible and inaccessible chromatin. We present experimental evidence of inaccessibility within heterochromatin regions in Neurospora, and we examine features of both accessible and inaccessible chromatin, including the presence of histone modifications, types of transcription, transcription factor binding, and relative nucleosome turnover rates. Chromatin accessibility is not strictly correlated with expression level. Accessible chromatin regions in the model filamentous fungus Neurospora are characterized the presence of H3K27 acetylation and commonly associated with pervasive non-coding transcription. Conversely, methylation of H3 lysine-36 catalyzed by ASH1 is correlated with inaccessible chromatin within promoter regions. Conclusions: In N. crassa, H3K27 acetylation is the most predictive histone modification for open chromatin. Conversely, our data show that H3K36 methylation is a key marker of inaccessible chromatin in gene-rich regions of the genome. Our data are consistent with an expanded role for H3K36 methylation in intergenic regions of filamentous fungi compared to the model yeasts, S. cerevisiae and S. pombe, which lack homologs of the ASH1 methyltransferase. of accessible chromatin in Neurospora
2020-11-12 | GSE154497 | GEO
Project description:Repression of facultative heterochromatin is essential for developmental processes in numerous organisms. Methylation of histone H3 lysine 27 (H3K27) by Polycomb repressive complex 2 is a prominent feature of facultative heterochromatin in both fungi and higher eukaryotes. Although this methylation is frequently crucial for silencing, the detailed mechanism of repression remains poorly understood. We utilized a forward genetics approach to identify three previously uncharacterized genes required to maintain silencing at facultative heterochromatin genes in Neurospora crassa: sds3 (NCU01599), rlp1 (RPD3L protein 1; NCU09007) and rlp2 (RPD3L protein 2; NCU02898). We found that SDS3, RLP1, and RLP2 associate with N. crassa homologs of the Saccharomyces cerevisiae RPD3L complex and are required for repression of a subset of H3K27-methylated genes. Loss of these genes does not lead to loss of H3K27 methylation but increases acetylation of histone H3 lysine 14 at upregulated genes, and SDS3 binding levels are highest at genes derepressed upon loss of sds3, rlp1, and rlp2, implying that RPD3L-driven deacetylation is a previously undescribed factor required for silencing of facultative heterochromatin in N. crassa.
2024-08-21 | GSE261327 | GEO
Project description:Repression of facultative heterochromatin is essential for developmental processes in numerous organisms. Methylation of histone H3 lysine 27 (H3K27) by Polycomb repressive complex 2 is a prominent feature of facultative heterochromatin in both fungi and higher eukaryotes. Although this methylation is frequently crucial for silencing, the detailed mechanism of repression remains poorly understood. We utilized a forward genetics approach to identify three previously uncharacterized genes required to maintain silencing at facultative heterochromatin genes in Neurospora crassa: sds3 (NCU01599), rlp1 (RPD3L protein 1; NCU09007) and rlp2 (RPD3L protein 2; NCU02898). We found that SDS3, RLP1, and RLP2 associate with N. crassa homologs of the Saccharomyces cerevisiae RPD3L complex and are required for repression of a subset of H3K27-methylated genes. Loss of these genes does not lead to loss of H3K27 methylation but increases acetylation of histone H3 lysine 14 at upregulated genes, and SDS3 binding levels are highest at genes derepressed upon loss of sds3, rlp1, and rlp2, implying that RPD3L-driven deacetylation is a previously undescribed factor required for silencing of facultative heterochromatin in N. crassa.
2024-08-21 | GSE261325 | GEO
Project description:Repression of facultative heterochromatin is essential for developmental processes in numerous organisms. Methylation of histone H3 lysine 27 (H3K27) by Polycomb repressive complex 2 is a prominent feature of facultative heterochromatin in both fungi and higher eukaryotes. Although this methylation is frequently crucial for silencing, the detailed mechanism of repression remains poorly understood. We utilized a forward genetics approach to identify three previously uncharacterized genes required to maintain silencing at facultative heterochromatin genes in Neurospora crassa: sds3 (NCU01599), rlp1 (RPD3L protein 1; NCU09007) and rlp2 (RPD3L protein 2; NCU02898). We found that SDS3, RLP1, and RLP2 associate with N. crassa homologs of the Saccharomyces cerevisiae RPD3L complex and are required for repression of a subset of H3K27-methylated genes. Loss of these genes does not lead to loss of H3K27 methylation but increases acetylation of histone H3 lysine 14 at upregulated genes, and SDS3 binding levels are highest at genes derepressed upon loss of sds3, rlp1, and rlp2, implying that RPD3L-driven deacetylation is a previously undescribed factor required for silencing of facultative heterochromatin in N. crassa.
2024-08-21 | GSE261319 | GEO
Project description:Establishing and maintaining appropriate gene repression is critical for the health and development of multicellular organisms. Histone H3 lysine 27 (H3K27) methylation is a chromatin modification associated with repressed facultative heterochromatin, but the mechanism of repression remains unclear. We used a forward genetic approach to identify novel genes involved in transcriptional silencing of H3K27 methylated chromatin in the filamentous fungus, Neurospora crassa. We found crf4-1Iswi and crf4-2Itc1/Acf1 are required for repression of a subset of H3K27 methylated genes and that their protein products interact to form an ACF-like chromatin remodeling complex. This N. crassa ACF-like complex is promiscuous, yet can target facultative heterochromatin, where it is responsible for pulling the +1 nucleosome in the 5’ direction. H3K27 methylated genes that are up-regulated when crf4-1Iswi or crf4-2Itc1/Acf1 are deleted show a downstream shift of the +1 nucleosome suggesting that proper nucleosome positioning is important for repression of facultative heterochromatin.
2022-03-08 | GSE168277 | GEO
Project description:Heterochromatin is a specialized form of chromatin that restricts access to DNA and inhibits genetic processes, including transcription and recombination. In Neurospora crassa, constitutive heterochromatin is characterized by trimethylation of lysine 9 on histone H3, hypoacetylation of histones, and DNA methylation. Here we explore whether the conserved histone demethylase, lysine-specific demethylase 1 (LSD1), regulates heterochromatin in Neurospora, and if so, how. Though LSD1 is implicated in heterochromatin regulation, its function is inconsistent across different systems; orthologs of LSD1 have been shown to either promote or antagonize heterochromatin expansion by removing H3K4me or H3K9me respectively. We identify three members of the Neurospora LSD complex (LSDC): LSD1, PHF1, and BDP-1, and strains deficient for any exhibit variable spreading of heterochromatin and establishment of new heterochromatin domains dispersed across the genome. Heterochromatin establishment outside of canonical domains in Neurospora share the unusual characteristic of DNA methylation-dependent H3K9me3; typically, H3K9me3 establishment is independent of DNA methylation. Consistent with this, the hyper-H3K9me3 phenotype of LSD1 knock-out strains is dependent on the presence of DNA methylation, as well as HCHC-mediated histone deacetylation, suggesting spreading is dependent on some feedback mechanism. Altogether, our results suggest LSD1 works in opposition to HCHC to maintain proper heterochromatin boundaries.
2021-07-21 | PXD017300 | Pride
Project description:Understanding how genomes encode complex cellular and organismal behaviors is an outstanding challenge of modern genetics. Unlike classical screening methods, analysis of the genetic variation that occurs naturally in wild populations can enable rapid, genome-scale trait mapping with a medium-throughput experimental design. Here we describe the results of the first genome-wide association analysis (GWAS) of a microbial eukaryote, using wild isolates of the filamentous fungus Neurospora crassa. We transcriptionally profiled each of 112 individuals collected in Louisiana and used RNA-seq data to genotype each strain at thousands of genetic loci genome-wide. We used these genotypes in a mapping analysis of microbial communication. In N. crassa, germinated asexual spores (germlings) sense the presence of other germlings, grow toward them in a coordinated fashion, and fuse. We evaluated germlings of each strain for their ability to chemically sense, chemotropically seek, and undergo cell fusion. GWAS identified one gene, NCU04379 (cse-1, encoding a homolog of neuronal calcium sensor), at which inheritance was strongly associated with the efficiency of germling communication. Deletion of cse-1 significantly lowered germling communication and fusion, and two genes encoding predicted binding partners of CSE-1 were also required for the communication trait. Additionally, mining our association results for signaling and secretion genes with a potential role in germling communication, we validated six more novel determinants of germling communication, including a secreted protease and two other genes whose deletion conferred a novel phenotype of increased communication and multi-germling fusion. These results establish protein secretion as a linchpin of germling communication in N. crassa and shed light on the regulation of communication molecules in this fungus. Our study demonstrates the power of population-genetic analyses for the rapid identification of genes contributing to complex traits in microbial species. 112 mycelial mRNA profiles of 16 hour wild type (WT) Neurospora crassa strains were generated by deep sequencing, using Illumina GAIIx.
2013-03-28 | E-GEOD-45406 | biostudies-arrayexpress
Project description:RNA-seq from Neurospora crassa at 5 time points of light induction, with 2 replicates for each, totalling 10 samples RNA-seq from Neurospora crassa at 5 time points of light induction, with 2 replicates for each, totalling 10 samples
2014-08-01 | E-GEOD-53534 | biostudies-arrayexpress