Extensive small RNAs sequestration in diverse eukaryotes
Ontology highlight
ABSTRACT:
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR562731.fastq.gz | Fastqsanger.gz | |||
| ERR562732.fastq.gz | Fastqsanger.gz | |||
| ERR562733.fastq.gz | Fastqsanger.gz | |||
| ERR562734.fastq.gz | Fastqsanger.gz | |||
| ERR562735.fastq.gz | Fastqsanger.gz |
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Project description:Dnmt1 epigenetically propagates symmetrical CG methylation in many eukaryotes. Their genomes are typically depleted of CG dinucleotides because of imperfect repair of deaminated methylcytosines. Here, we extensively survey diverse species lacking Dnmt1 and show that, surprisingly, symmetrical CG methylation is nonetheless frequently present and catalyzed by a different DNA methyltransferase family, Dnmt5. Numerous Dnmt5-containing organisms that diverged more than a billion years ago exhibit clustered methylation, specifically in nucleosome linkers. Clustered methylation occurs at unprecedented densities and directly disfavors nucleosomes, contributing to nucleosome positioning between clusters. Dense methylation is enabled by a regime of genomic sequence evolution that enriches CG dinucleotides and drives the highest CG frequencies known. Species with linker methylation have small, transcriptionally active nuclei that approach the physical limits of chromatin compaction. These features constitute a previously unappreciated genome architecture, in which dense methylation influences nucleosome positions, likely facilitating nuclear processes under extreme spatial constraints. DNA methylation, RNA and nucleosome sequencing data for diverse eukaryotes
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Project description:Dnmt1-Independent CG Methylation Contributes to Nucleosome Positioning in Diverse Eukaryotes
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Project description:Dnmt1 epigenetically propagates symmetrical CG methylation in many eukaryotes. Their genomes are typically depleted of CG dinucleotides because of imperfect repair of deaminated methylcytosines. Here, we extensively survey diverse species lacking Dnmt1 and show that, surprisingly, symmetrical CG methylation is nonetheless frequently present and catalyzed by a different DNA methyltransferase family, Dnmt5. Numerous Dnmt5-containing organisms that diverged more than a billion years ago exhibit clustered methylation, specifically in nucleosome linkers. Clustered methylation occurs at unprecedented densities and directly disfavors nucleosomes, contributing to nucleosome positioning between clusters. Dense methylation is enabled by a regime of genomic sequence evolution that enriches CG dinucleotides and drives the highest CG frequencies known. Species with linker methylation have small, transcriptionally active nuclei that approach the physical limits of chromatin compaction. These features constitute a previously unappreciated genome architecture, in which dense methylation influences nucleosome positions, likely facilitating nuclear processes under extreme spatial constraints.
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Project description:A variety of small RNAs, including the Dicer-dependent miRNAs and the Dicer-independent Piwi-interacting RNAs, associate with Argonaute family proteins to regulate gene expression in diverse cellular processes. These two species of small RNA have not been found in fungi. Here, by analyzing small RNA associated with the Neurospora Argonaute protein QDE-2, we show that diverse pathways generate miRNA-like small RNAs (milRNAs) and Dicer-independent small interfering RNAs (disiRNAs) in this filamentous fungus. Surprisingly, milRNAs are produced by at least four different mechanisms that use a distinct combination of factors, including Dicers, QDE-2, the exonuclease QIP and an RNAse III domain-containing protein MRPL3. In contrast, disiRNAs originate from loci producing overlapping sense and antisense transcripts, and do not require the known RNAi components for their production. Taken together, these results uncover several pathways for small RNA production in filamentous fungi, shedding light on the diversity and evolutionary origins of eukaryotic small RNAs. One small RNA library was generated using QDE-2 immunoprecipitate from Neurospora crassa.
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Project description:Dictyostelium discoideum behavior depends on nutrients1. When sufficient food is present these amoebae exist in a unicellular state, but upon starvation they aggregate into a multicellular organism2,3. This unique biology makes D. discoideum an ideal model for investigating how fundamental metabolic pathways command cell differentiation and function. We show here that reactive oxygen species (ROS), generated as a consequence of nutrient limitation, lead to the sequestration of the amino acid cysteine in the antioxidant glutathione, limiting the use of its sulfur atom for processes such as protein translation and FeS cluster-containing enzyme activity that contribute to mitochondrial metabolism and cellular proliferation. Such regulated sulfur sequestration maintains D. discoideum in a non-proliferating state that paves the way for multicellular development. This new mechanism of ROS signaling highlights oxygen and sulfur as simple, early evolutionary signaling molecules dictating cell fate, with implications for responses to nutrient fluctuations in higher eukaryotes.
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Project description:A variety of small RNAs, including the Dicer-dependent miRNAs and the Dicer-independent Piwi-interacting RNAs, associate with Argonaute family proteins to regulate gene expression in diverse cellular processes. These two species of small RNA have not been found in fungi. Here, by analyzing small RNA associated with the Neurospora Argonaute protein QDE-2, we show that diverse pathways generate miRNA-like small RNAs (milRNAs) and Dicer-independent small interfering RNAs (disiRNAs) in this filamentous fungus. Surprisingly, milRNAs are produced by at least four different mechanisms that use a distinct combination of factors, including Dicers, QDE-2, the exonuclease QIP and an RNAse III domain-containing protein MRPL3. In contrast, disiRNAs originate from loci producing overlapping sense and antisense transcripts, and do not require the known RNAi components for their production. Taken together, these results uncover several pathways for small RNA production in filamentous fungi, shedding light on the diversity and evolutionary origins of eukaryotic small RNAs.
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