Project description:A majority of metazoan mRNAs are under microRNA (miRNA)/Argonaute (Ago)-mediated control of RNA stability at the post-transcriptional level. Although the molecular mechanism of the miRNA-mediated repression of target mRNAs through Ago/TNRC6 pathway have been largely elucidated, however, the existence of alternative TNRC6-independent miRNA-mediated post-transcriptional gene regulation pathway remains unknown. Here, we suggest that endogenous miRNAs (endo-miRNAs) can downregulate the target mRNAs via the alternative molecular pathway, Ago-associated UPF1/SMG7, core mediators of nonsense-mediated mRNA decay. Global analyses of mRNAs in a response to UPF1 RNA interference in miRNA-deficient cells reveal that 3’UTR-length-dependent mRNA decay by UPF1 requires endo-miRNA targeting via CUG motif. The repression of miRNA targets is more additively or synergistically accomplished by combination of Ago2 and UPF1 through UPF1-associated SMG7, recruiting CCR4-NOT deadenylase complex, in TNRC6-independent manner. We expect that the new miRNA-mediated mRNA decay pathway enables the miRNA targeting to become more predictable and expand the miRNA-mRNA regulatory network.
Project description:Analysis of cellular NMD (Nonsense-mediated mRNA decay) substrates that regulated by Upf1, SMG5, SMG7 and/or PNRC2 in HeLa cell. The hypothesis tested in the present study was that endogenous NMD substrates may co-regulated by Upf1, SMG5, SMG7 and PNRC2.
Project description:Nonsense-mediated mRNA decay (NMD) is a conserved RNA surveillance pathway that is an important modulator of disease pathology and is required for embryonic development. Despite significant research effort, the rules that govern NMD remain incompletely understood. Here we used a combined¬ approach, integrating RNA-Seq, ribosome footprinting, and CLIP-Seq analysis of the essential NMD factor Upf1, to provide a more complete picture of the role of NMD in modulating gene expression in murine embryonic stem cells (mESCs). We show that presence of an exon-exon junction ?50 nucleotides (nt) downstream of a termination codon (dEJ) contributes to NMD independently of 3' UTR length, but has stronger effects in genes with shorter 3' UTRs. We also map translated upstream open reading frames (uORFs) in mESCs and show that they are associated with NMD regulation, especially of genes encoding transcription factors, and we find that lowly translated mRNAs can escape NMD. Finally, we identify over 200 direct binding targets of Upf1 and describe a pathway of Upf1-dependent gene regulation reliant on Upf1 binding to the 3' UTR and independent of presence of a dEJ. Together, these analyses characterize known and discover novel determinants of NMD and establish a broader role in mESC gene regulation for Upf1. mRNA-Seq analysis of wildtype (2 samples), translationally inhibited (by cycloheximide treatment, 2 samples), control-depleted (2 samples), and Upf1-depleted (4 samples) mouse embryonic stem cells (mESCs); CLIP-Seq analysis of Upf1 (5 samples, and 5 samples of IgG control CLIP-Seq); Ribosome footprint profiling of wildtype (1 sample), control-depleted (1 sample), and Upf1-depleted (1 sample) mESCs
Project description:We have HA-tagged two nonsense-mediated decay proteins, UPF1 and UPF2, in the malaria parasite Plasmodium falciparum. We then performed co-immunoprecipitation experiments to determine the protein-protein interactions of these nonsense-mediated decay components.
Project description:RNA helicases are important regulators of gene expression that act by remodeling RNA secondary structures and as RNA-protein interactions. Here, we demonstrate that MOV10 has an ATP-dependent 5' to 3' in vitro RNA unwinding activity and determine the RNA-binding sites of MOV10 and its helicase mutants using PAR-CLIP. We find that MOV10 predominantly binds to 3' UTRs upstream of regions predicted to form local secondary structures and provide evidence that MOV10 helicase mutants are impaired in their ability to translocate 5' to 3' on their mRNA targets. MOV10 interacts with UPF1, the key component of the nonsense-mediated mRNA decay pathway. PAR-CLIP of UPF1 reveals that MOV10 and UPF1 bind to RNA in close proximity. Knockdown of MOV10 resulted in increased mRNA half-lives of MOV10-bound as well as UPF1-regulated transcripts, suggesting that MOV10 functions in UPF1-mediated mRNA degradation as an RNA clearance factor to resolve structures and displace proteins from 3' UTRs. Flp-In T-REx HEK293 cells expressing FLAG/HA-tagged MOV10 WT, MOV10 K530A, MOV10 D645N and UPF1 were sequenced. mRNA half-life data under GSE56751.
Project description:RNA helicases are important regulators of gene expression that act by remodeling RNA secondary structures and as RNA-protein interactions. Here, we demonstrate that MOV10 has an ATP-dependent 5' to 3' in vitro RNA unwinding activity and determine the RNA-binding sites of MOV10 and its helicase mutants using PAR-CLIP. We find that MOV10 predominantly binds to 3' UTRs upstream of regions predicted to form local secondary structures and provide evidence that MOV10 helicase mutants are impaired in their ability to translocate 5' to 3' on their mRNA targets. MOV10 interacts with UPF1, the key component of the nonsense-mediated mRNA decay pathway. PAR-CLIP of UPF1 reveals that MOV10 and UPF1 bind to RNA in close proximity. Knockdown of MOV10 resulted in increased mRNA half-lives of MOV10-bound as well as UPF1-regulated transcripts, suggesting that MOV10 functions in UPF1-mediated mRNA degradation as an RNA clearance factor to resolve structures and displace proteins from 3' UTRs.
Project description:RNA helicases are important regulators of gene expression that act by remodeling RNA secondary structures and as RNA-protein interactions. Here, we demonstrate that MOV10 has an ATP-dependent 5' to 3' in vitro RNA unwinding activity and determine the RNA-binding sites of MOV10 and its helicase mutants using PAR-CLIP. We find that MOV10 predominantly binds to 3' UTRs upstream of regions predicted to form local secondary structures and provide evidence that MOV10 helicase mutants are impaired in their ability to translocate 5' to 3' on their mRNA targets. MOV10 interacts with UPF1, the key component of the nonsense-mediated mRNA decay pathway. PAR-CLIP of UPF1 reveals that MOV10 and UPF1 bind to RNA in close proximity. Knockdown of MOV10 resulted in increased mRNA half-lives of MOV10-bound as well as UPF1-regulated transcripts, suggesting that MOV10 functions in UPF1-mediated mRNA degradation as an RNA clearance factor to resolve structures and displace proteins from 3' UTRs.
Project description:Analysis of cellular NMD (Nonsense-mediated mRNA decay) substrates that regulated by Upf1, SMG5, SMG7 and/or PNRC2 in HeLa cell. The hypothesis tested in the present study was that endogenous NMD substrates may co-regulated by Upf1, SMG5, SMG7 and PNRC2. Total RNA obtained from HeLa cells with downregulation of Upf1, SMG5, PNRC2 or SMG7 by siRNA. The up- or down-regulated transcripts were compare to control siRNA treated HeLa cell RNA extract. Significant transcripts were confirmed by replication
Project description:RNA helicases are important regulators of gene expression that act by remodeling RNA secondary structures and as RNA-protein interactions. Here, we demonstrate that MOV10 has an ATP-dependent 5' to 3' in vitro RNA unwinding activity and determine the RNA-binding sites of MOV10 and its helicase mutants using PAR-CLIP. We find that MOV10 predominantly binds to 3' UTRs upstream of regions predicted to form local secondary structures and provide evidence that MOV10 helicase mutants are impaired in their ability to translocate 5' to 3' on their mRNA targets. MOV10 interacts with UPF1, the key component of the nonsense-mediated mRNA decay pathway. PAR-CLIP of UPF1 reveals that MOV10 and UPF1 bind to RNA in close proximity. Knockdown of MOV10 resulted in increased mRNA half-lives of MOV10-bound as well as UPF1-regulated transcripts, suggesting that MOV10 functions in UPF1-mediated mRNA degradation as an RNA clearance factor to resolve structures and displace proteins from 3' UTRs. Flp-In T-REx HEK293 cells expressing FLAG/HA-tagged MOV10 WT, MOV10 K530A, MOV10 D645N and UPF1 were used to determine the protein-RNA interaction sites of RNA helicases MOV10 and UPF1 as well as MOV10 inactive variants using PAR-CLIP in combination with next generation sequencing. mRNA half-life changes of MOV10-targeted mRNA were determined by measuring mRNA half-lives by mRNA sequencing of mock and MOV10-depleted HEK293 cells.
Project description:Nonsense-mediated mRNA decay (NMD) controls gene expression by eliminating mRNAs with premature or aberrant translation termination. Degradation of NMD substrates is initiated by the central NMD factor UPF1, which recruits the endonuclease SMG6 and the deadenylation-promoting SMG5/7 complex. Here we map transcriptome-wide sites of SMG6-mediated endocleavage via 3′ fragment capture and degradome sequencing.