Mtr4-like protein coordinates nuclear RNA processing for heterochromatin assembly and for telomere maintenance
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ABSTRACT:
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR351446.fastq.gz | Fastqsanger.gz | |||
| ERR351447.fastq.gz | Fastqsanger.gz | |||
| ERR351448.fastq.gz | Fastqsanger.gz | |||
| ERR351449.fastq.gz | Fastqsanger.gz | |||
| ERR351450.fastq.gz | Fastqsanger.gz |
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Project description:The regulation of protein-coding and noncoding RNAs is linked to nuclear processes, including chromatin modifications and gene silencing. However, the mechanisms that distinguish RNAs and mediate their functions are poorly understood. We describe a nuclear RNA-processing network in fission yeast with a core module comprising the Mtr4-like protein, Mtl1, and the zinc-finger protein, Red1. The Mtl1-Red1 core promotes degradation of mRNAs and noncoding RNAs and associates with different proteins to assemble heterochromatin via distinct mechanisms. Mtl1 also forms Red1-independent interactions with evolutionarily conserved proteins named Nrl1 and Ctr1, which associate with splicing factors. Whereas Nrl1 targets transcripts with cryptic introns to form heterochromatin at developmental genes and retrotransposons, Ctr1 functions in processing intron-containing telomerase RNA. Together with our discovery of widespread cryptic introns, including in noncoding RNAs, these findings reveal unique cellular strategies for recognizing regulatory RNAs and coordinating their functions in response to developmental and environmental cues.
| S-EPMC3974623 | biostudies-literature
Project description:Histones of heterochromatin are deacetylated in yeast and methylated in more complex eukaryotes to regulate heterochromatin structure and gene silencing. Here, we report that histone H2A phosphorylated at serine 129 (γH2A) in Saccharomyces cerevisiae is a conceptually new type of heterochromatin modification that functions downstream of silent chromatin assembly. We show that γH2A is enriched throughout yeast telomeric and silent mating locus (HM) heterochromatin where γH2A results from the action of kinases Tel1 and Mec1. Interestingly, mutation of γH2A has no apparent effect on the binding of Sir (silent information regulator) complex or on gene silencing. In contrast, deletion of SIR3 abolishes the formation of γH2A at heterochromatin. To address the function of γH2A, we used a ∆rif1 mutant strain in which telomeres are excessively elongated to show that γH2A is required for the optimal recruitment of Cdc13, a regulator of telomere elongation, and for telomere elongation itself. Thus, a histone modification that parallels Sir3 protein binding is shown here to be dispensable for the formation of a silent structure but is important for a crucial heterochromatin-specific downstream function in telomere homeostasis.
2011-01-05 | GSE21814 | GEO
Project description:Metabolic switch from oxidative phosphorylation to glycolysis is required for tumorigenesis by providing cancer cells with energy and substrates of biosynthesis, and also plays a key role in inducing immune suppressive tumor microenvironment that inhibits tumor immunotherapy. Therefore, to develop more effective cancer therapy, it is important to elucidate mechanisms that control cancer metabolic switch. MTR4 is a RNA helicase associated with nuclear exosome that plays key roles in RNA processing and surveillance. We demonstrated that MTR4 is frequently overexpressed in hepatocellular carcinoma (HCC) and this predicts poor prognosis of HCC patients. MTR4 is required for HCC tumorigenesis by maintaining cancer metabolic switch. Mechanistically, MTR4 is required for the expression of critical glycolytic proteins such as GLUT1 and PKM2 by binding to their pre-mRNA and ensuring correct alternative splicing. c-Myc binds to the promoter of MTR4 gene and is required for MTR4 expression, indicating that MTR4 is a key mediator of c-Myc function in promoting cancer metabolism. These findings reveal an important pathway to drive cancer metabolic switch and present MTR4 as a promising therapeutic target for treating HCC.
2019-12-19 | GSE129261 | GEO
Project description:SMUG1 promotes telomere maintenance through telomerase RNA end-processing
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Project description:til-ath-2011_3 - tiling hen2 and mtr4 - Identification and comparison of the RNA substrates that accumulate in hen2 and mtr4 mutants. Total RNA extracted from WT, hen2 and mtr4 mutants was used for oligo-dT primed cDNA preparation. Samples were hybridised to NimbleGen whole genome tiling arrays. 8 dye-swapped samples. Gene knockout, genotype comparison, normal vs. transgenic comparison.
2013-06-30 | E-GEOD-48178 | biostudies-arrayexpress
Project description:The glycolytic enzyme, pyruvate kinase Pyk1 maintains telomere heterochromatin by phosphorylating histone H3T11 (H3pT11), which promotes SIR (silent information regulator) complex binding at telomeres and prevents autophagy-mediated Sir2 degradation. However, the exact action mechanism of H3pT11 is poorly understood. Here, we report that H3pT11 directly inhibits Dot1-catalyzed H3K79 tri-methylation (H3K79me3) and uncover how this histone crosstalk regulates autophagy and telomere silencing. Mechanistically, Pyk1-catalyzed H3pT11 directly reduces the binding of Dot1 to chromatin and inhibits Dot1-catalyzed H3K79me3, which leads to transcriptional repression of autophagy genes and reduced autophagy. Despite the antagonism between H3pT11 and H3K79me3, they work together to promote the binding of SIR complex at telomeres to maintain telomere silencing. Furthermore, we identify Reb1 as a telomere-associated factor that recruits Pyk1-containing SESAME (Serine-responsive SAM36 taining Metabolic Enzyme) complex to telomere regions to phosphorylate H3T11 and prevent the invasion of H3K79me3 from euchromatin into heterochromatin to maintain telomere silencing. Together, these results uncover a novel histone crosstalk and provide insights into dynamic regulation of silent heterochromatin and autophagy in response to cell metabolism.
2023-02-07 | PXD038138 | Pride
Project description:Telomeres are organized into a heterochromatin structure and maintenance of silent heterochromatin is required for chromosome stability. How telomere heterochromatin is dynamically regulated in response to stimuli remains unknown. Pyruvate kinase Pyk1 forms a complex, named SESAME (Serine-responsive SAM-containing Metabolic Enzyme complex) to regulate gene expression by phosphorylating histone H3T11 (H3pT11). Here, we identified a novel function of SESAME in regulating telomere heterochromatin structure. SESAME phosphorylates H3T11 at telomeres, which promotes SIR (silent information regulator) complex assembly at telomeres and protects Sir2 from degradation by autophagy. Moreover, SESAMEcatalyzed H3pT11 directly represses autophagy-related gene expression to further prevent autophagy-mediated Sir2 degradation. By promoting H3pT11, serine increases Sir2 protein levels and enhances telomere silencing. Loss of H3pT11 leads to reduced Sir2 and compromised telomere silencing during chronological aging. Together, our study provides insights into dynamic regulation of silent heterochromatin by histone modifications and autophagy in response to cell metabolism and aging.
2020-12-04 | GSE147050 | GEO
Project description:Mtr4 is a eukaryotic RNA helicase required for RNA decay by the nuclear exosome. Previous studies have shown how RNA enroute to the exosome threads through the highly conserved helicase core of Mtr4. Mtr4 also contains an arch domain, although details of potential interactions between the arch and RNA have been elusive. To understand the interaction of Saccharomyces cerevisiae Mtr4 with various RNAs, we have characterized RNA binding in solution using hydrogen-deuterium exchange mass spectrometry, and affinity and unwinding assays. We have identified RNA interactions within the helicase core that are consistent with existing structures and do not vary between tRNA, single-stranded RNA, and double-stranded RNA constructs. We have also identified novel RNA interactions with a region of the arch known as the fist or KOW. These interactions are important for RNA unwinding and vary in strength depending on RNA structure and length. They account for Mtr4 discrimination between different RNAs. These interactions further drive Mtr4 to adopt a closed conformation characterized by reduced dynamics of the arch arm and intra-domain contacts between the fist and helicase core.
2022-03-07 | PXD031962 | Pride
Project description:To investigate the role of the helicases Dbp2 and Mtr4 in the decay of Xrn1-sensitive lncRNAs, we performed RNA-Seq in yeast cells lacking Dbp2 or depleted for Mtr4.
2023-07-27 | GSE235552 | GEO
Project description:Telomeric Repeat-containing RNA are long non-coding RNAs generated from the telomeres. TERRAs are essential for the establishment of heterochromatin marks at telomeres, which serve for the binding of members of the Heterochromatin Protein 1protein family of epigenetic modifiers involved with chromatin compaction and gene silencing. While HP1γ is enriched on gene bodies of actively transcribed mammalian genes, it is unclear if its transcriptional role is important for HP1γ function in telomere cohesion and telomere maintenance. We aimed to study the effect of mouse HP1γ on the transcription of telomere factors and molecules that can affect telomere maintenance. We investigated the telomere function of HP1γ by using HP1γ deficient mouse embryonic fibroblastsderiving from 13.5 embryonic day embryos compared to their littermate controls. We used gene expression analysis of HP1γ deficient MEFs and validated the molecular and mechanistic consequences of HP1γ loss by telomere FISH, immunofluorescence, RT-qPCR and DNA-RNA Immunoprecipitation. Loss of HP1γ in primary MEFs led to a downregulation of various telomere and telomere-accessory transcripts, including the shelterin protein TRF1. Its downregulation is associated with increased telomere replication stress and DNA damage (γH2AX), effects more profound in females. We suggest that the source for the impaired telomere maintenance is a consequence of increased telomeric DNARNA hybrids and TERRAs arising at and from mouse chromosomes 18 and X. Our results suggest an important transcriptional control by mouse HP1γ of various telomere factors including TRF1 protein and TERRAs that has profound consequences on telomere stability, with a potential sexually dimorphic nature.
2023-08-19 | GSE240434 | GEO