Pseudouridylation of tRNA-derived fragments steers translation control in stem cells [Polysome-Seq]
Ontology highlight
ABSTRACT: Pseudouridylation (pseudouridine) is the most abundant and widespread type of RNA epigenetic modification in living organisms; however, the biological role of pseudouridine remains poorly understood. Here, we show that a pseudouridine-driven posttranscriptional program steers translation control to impact stem cell commitment during early embryogenesis. Mechanistically, the pseudouridine ‘writer’ PUS7 modifies and activates a network of tRNA-derived fragments (tRFs) targeting the translation initiation complex. PUS7 inactivation in embryonic stem cells impairs tRF-mediated translational regulation leading to high protein biosynthesis and abnormal germ layer specification. Dysregulation of PUS7 and tRFs in myeloid malignancies associates with altered translation rates, suggesting a role of pseudouridine in tumorigenesis. Our findings unveil a critical function of pseudouridine in directing translational control in stem cells with promisingly broad implications for human disease.
Project description:Pseudouridylation (Ψ) is the most abundant and widespread type of RNA epigenetic modification in living organisms; however, the biological role of Ψ remains poorly understood. Here, we show that a Ψ-driven posttranscriptional program steers translation control to impact stem cell commitment during early embryogenesis. Mechanistically, the Ψ ‘writer’ PUS7 modifies and activates a network of tRNA-derived fragments (tRFs) targeting the translation initiation complex. PUS7 inactivation in embryonic stem cells impairs tRF-mediated translational regulation leading to high protein biosynthesis and abnormal germ layer specification. Dysregulation of PUS7 and tRFs in myeloid malignancies associates with altered translation rates, suggesting a role of Ψ in tumorigenesis. Our findings unveil a critical function of Ψ in directing translational control in stem cells with promisingly broad implications for human disease.
Project description:Pseudouridylation (Ψ) is the most abundant and widespread type of RNA epigenetic modification in living organisms; however, the biological role of Ψ remains poorly understood. Here, we show that a Ψ-driven posttranscriptional program steers translation control to impact stem cell commitment during early embryogenesis. Mechanistically, the Ψ ‘writer’ PUS7 modifies and activates a network of tRNA-derived fragments (tRFs) targeting the translation initiation complex. PUS7 inactivation in embryonic stem cells impairs tRF-mediated translational regulation leading to high protein biosynthesis and abnormal germ layer specification. Dysregulation of PUS7 and tRFs in myeloid malignancies associates with altered translation rates, suggesting a role of Ψ in tumorigenesis. Our findings unveil a critical function of Ψ in directing translational control in stem cells with promisingly broad implications for human disease.
Project description:Pseudouridylation (Ψ) is the most abundant and widespread type of RNA epigenetic modification in living organisms; however, the biological role of Ψ remains poorly understood. Here, we show that a Ψ-driven posttranscriptional program steers translation control to impact stem cell commitment during early embryogenesis. Mechanistically, the Ψ ‘writer’ PUS7 modifies and activates a network of tRNA-derived fragments (tRFs) targeting the translation initiation complex. PUS7 inactivation in embryonic stem cells impairs tRF-mediated translational regulation leading to increased protein biosynthesis and abnormal germ layer specification. Remarkably, dysregulation of PUS7 and tRFs in myeloid malignancies associates with altered translation rates, suggesting a role of Ψ in leukemogenesis. Our findings unveil a critical function of Ψ in directing translational control in stem cells with important implications for human disease.
Project description:Pseudouridine is the first discovered and the most frequent modification in RNA. However, its biological functions in physiology and human diseases are largely unknown. Here, we show that pseudouridine synthase PUS7 is differentially expressed in glioblastoma patient tissues verse non-tumor brain tissues, and highly expressed in patient brain-derived cancer stem cells, compared to normal brain-derived neural stem cells. Upregulated expression of PUS7 predicts worse survival in glioblastoma patients in multiple databases. Indeed, we show that PUS7 plays an important role in regulating the self-renewal and tumorigenesis of glioblastoma stem cells. Overexpression of the wild type but not the catalytically inactive PUS7 increases the growth and self-renewal of GSCs. In contrast, knockdown of PUS7 dramatically suppresses GSC growth, self-renewal and tumorigenesis. Mechanistically, knockdown of PUS7 activates interferon pathway through translational control of TYK2 via PUS7-regulated tRNAs. Moreover, we have identified chemical inhibitors for PUS7 in this study. These chemical compounds target pseudouridine modification and suppress GSC growth and tumorigenesis, providing a potential therapeutic tool for GBM treatment.
Project description:Pseudouridine is the most abundant modification occurring on RNA, yet with the exception of a few well-studied RNA molecules little is known about the modified positions and their function(s). Here, we develop M-NM-(-seq, a method for transcriptome-wide quantitative mapping of pseudouridine. We validate M-NM-(-seq with synthetic spike-ins and de novo identification of the vast majority of previously reported pseudouridylated positions. M-NM-(-seq permits discovery of hundreds of novel pseudouridine modifications in human and yeast mRNAs and snoRNAs. Knockdown and knockout of pseudouridine synthases uncovers the cognate PUSs mediating pseudouridine catalysis at these individual novel sites and their target sequence features. In both human and yeast pseudouridine formation on mRNA depends on both site-specific PUSs M-bM-^@M-^S often guided by a specific sequence motif - and snoRNA-guided PUSs. Importantly, upon heat shock in yeast, Pus7-mediated pseudouridylation is induced at >200 sites in diverse mRNAs. Pus7 deletion in yeast leads to decreased recovery from heat shock and decreased RNA levels at otherwise pseudouridylated messages, suggesting a role for pseudouridine in enhancing transcript stability. Pseudouridine stoichiometries in rRNA are highly conserved from yeast to mammals, but are reduced in cells derived from dyskeratosis congenita patients, where the pseudouridine synthase DKC1 is mutated, compared to age matched controls. Our results establish pseudouridine as a ubiquitous and dynamic modification in mRNA, and provide a sensitive, quantitative and transcriptome-wide methodology to address its underlying mechanisms and function. Examination of m6A methylation in human Hek293 and A549 cell lines, in human embryonic stem cells (ESCs) undergoing differentiation to neural progenitor cells (NPCs), in OKMS inducible fibroblasts reprogrammed into iPSC, and upon knockdown of factors using siRNAs or shRNAs.
Project description:In this accession we provide pseudouridylation measurements upon knockdown and/or overexpression three pseudouridine synthases, two of which (TRUB1 and PUS7) we find to be with predominant activity on mammalian mRNA.
Project description:Pseudouridine is the most abundant modification occurring on RNA, yet with the exception of a few well-studied RNA molecules little is known about the modified positions and their function(s). Here, we develop Ψ-seq, a method for transcriptome-wide quantitative mapping of pseudouridine. We validate Ψ-seq with synthetic spike-ins and de novo identification of the vast majority of previously reported pseudouridylated positions. Ψ-seq permits discovery of hundreds of novel pseudouridine modifications in human and yeast mRNAs and snoRNAs. Knockdown and knockout of pseudouridine synthases uncovers the cognate PUSs mediating pseudouridine catalysis at these individual novel sites and their target sequence features. In both human and yeast pseudouridine formation on mRNA depends on both site-specific PUSs – often guided by a specific sequence motif - and snoRNA-guided PUSs. Importantly, upon heat shock in yeast, Pus7-mediated pseudouridylation is induced at >200 sites in diverse mRNAs. Pus7 deletion in yeast leads to decreased recovery from heat shock and decreased RNA levels at otherwise pseudouridylated messages, suggesting a role for pseudouridine in enhancing transcript stability. Pseudouridine stoichiometries in rRNA are highly conserved from yeast to mammals, but are reduced in cells derived from dyskeratosis congenita patients, where the pseudouridine synthase DKC1 is mutated, compared to age matched controls. Our results establish pseudouridine as a ubiquitous and dynamic modification in mRNA, and provide a sensitive, quantitative and transcriptome-wide methodology to address its underlying mechanisms and function.
Project description:Post-transcriptional modifications of mRNA have emerged as novel regulators of gene expression. Pseudouridylation is the most abundant and widespread type of RNA modification in living organisms; however, the biological role of pseudouridine in mRNAs remains poorly understood. Here, we show that the pseudouridine synthase dyskerin associates with RNA polymerase II and is enriched at RNA polymerase II-transcribed genes genome-wide. As part of the H/ACA complex, dyskerin binds to thousands of mRNAs and is responsible for their pseudouridylation, an action that occurs in chromatin and does not appear to require a fully complementary guide RNA. In cells lacking dyskerin, pseudouridylation of mRNAs is reduced, while at the same time, de novo protein production is enhanced, indicating that pseudouridylation of mRNAs by dyskerin interferes with translation. Accordingly, pseudouridylation of an mRNA by dyskerin in vitro results in reduced translation of that mRNA. Moreover, in patients with dyskeratosis congenita caused by inherited mutations in the DKC1 gene, binding between mutated dyskerin and mRNAs is altered and pseudouridylation of mRNAs severely reduced. Our findings reveal a new critical function of the H/ACA complex in directing translation control with important implications for development and disease.
Project description:Post-transcriptional modifications of mRNA have emerged as novel regulators of gene expression. Pseudouridylation is the most abundant and widespread type of RNA modification in living organisms; however, the biological role of pseudouridine in mRNAs remains poorly understood. Here, we show that the pseudouridine synthase dyskerin associates with RNA polymerase II and is enriched at RNA polymerase II-transcribed genes genome-wide. As part of the H/ACA complex, dyskerin binds to thousands of mRNAs and is responsible for their pseudouridylation, an action that occurs in chromatin and does not appear to require a fully complementary guide RNA. In cells lacking dyskerin, pseudouridylation of mRNAs is reduced, while at the same time, de novo protein production is enhanced, indicating that pseudouridylation of mRNAs by dyskerin interferes with translation. Accordingly, pseudouridylation of an mRNA by dyskerin in vitro results in reduced translation of that mRNA. Moreover, in patients with dyskeratosis congenita caused by inherited mutations in the DKC1 gene, binding between mutated dyskerin and mRNAs is altered and pseudouridylation of mRNAs severely reduced. Our findings reveal a new critical function of the H/ACA complex in directing translation control with important implications for development and disease.