Project description:Pseudouridine synthases (PUSs) are responsible for the installation of pseudouridine (Ψ) modification in RNA. However, the activity and function of the PUS enzymes remain largely unexplored. Here we focus on human PUS10 and find that it co-expresses with the microprocessor (DROSHA–DGCR8 complex). Depletion of PUS10 results in a marked reduction of the expression level of a large number of mature miRNAs and concomitant accumulation of unprocessed primary microRNAs (pri-miRNAs) in multiple human cells. Mechanistically, PUS10 directly binds to pri-miRNAs and interacts with the microprocessor to promote miRNA biogenesis. Unexpectedly, this process is independent of the catalytic activity of PUS10. Additionally, we develop a sequencing method to profile Ψ in the tRNAome and report PUS10-dependent Ψ sites in tRNA. Collectively, our findings reveal differential functions of PUS10 in nuclear miRNA processing and in cytoplasmic tRNA pseudouridylation.
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: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 (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:Pseudo-seq was used to measure differences in the extent of pseudouridine (Ψ) modification in rRNA from mice haploinsufficient for the H/ACA biogenesis factor Naf1 compared to wild- type. We measured telomerase RNA levels as well as a sample of box H/ACA RNAs and found they were all decreased in Naf1+/- mice. Nevertheless, Naf1+/- mice had minimally decreased levels of pseudouridylation at the rRNA sites queried. This was not associated with any phenotypic abnormalities in vivo in these mice which we examined for hematopoeitic, liver, testes and brain defects. CMC treatment of RNA followed by next generation sequencing was used to measure the extent of pseudouridylation at mapped mouse rRNA Ψ sites.
Project description:Pseudouridine (Ψ) is the most abundant RNA modification, yet little is known about its content, dynamics and function in mRNA and ncRNA. Here, we perform quantitative MS analysis and develop CAP-seq for transcriptome-wide Ψ profiling. The unexpected high Ψ content (Ψ/U ratio: ~ 0.2% to 0.6%) indicates that pseudouridylation in mammalian mRNA is much more prevalent and comprehensive than previously believed. In concordance, CAP-seq identified 2,084 Ψ sites within 1,929 human transcripts. We prove four previously unknown Ψ sites in rRNA and EEF1A1 mRNA. Genetic and biochemical analysis uncover PUS1 as a major human mRNA Ψ synthase. In response to stimuli, Ψ level and sites are dynamically modulated in stimulus-specific manners. Comparisons between human and mouse pseudouridylation reveal conserved and unique sites across tissue and species. We observe stop codon pseudouridylation and readthrough events simultaneously for HSPB1 mRNA, indicating a role in nonsense suppression. Together, these approaches allow in-depth analysis of transcriptome-wide pseudouridylation events and our comprehensive study provides a resource for functional studies of Ψ-mediated epigenetic regulation. Here we report a transcriptome-wide profiling method that utilizes a chemically synthesized N3-CMC, which pre-enriches the Ψ-containing RNAs and blocks the reverse transcription.Mapping the Ψ sites in human transcriptome was performed using HEK293T and PUS1 dependent Ψ sites were identified by comparing PUS1 knock out cells with wildtype cells. Stress inducible or suppressed Ψ sites were identified by comparing stress treated cells with untreated cells. And mouse brain and liver were used to map Ψ sites in mouse transcriptome.
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.