Project description:The goal of the project was to study the effects on transcription and mRNA stability of the Xrn1 sudden depletion. We analyzed the effect of Xrn1 depletion caused by protein degradation of an Auxin-degron fusion on the transcription rates, mRNA stabilities and mRNA levels by doing Genomic Run-On (GRO) experiments at 30 min after Auxin addition with a control at 0 min.
Project description:XRN1 is a cytoplasmic 5’-3’ exoribonuclease responsible for degradation of multiple types of RNA. Data obtained on yeast model described XRN1 function in degradation of messenger (m)RNA, Rapid transfer (t)RNA Decay (RTD) of hypomodified and unstable tRNA transcripts as well as maturation of 25S ribosomal (r)RNA and small nucleolar (sno)RNAs. Our group discovered previously that deletion of XRN1 gene results in stabilization of a group of long non-coding RNAs, which are often transcribed antisense to protein-coding genes and may regulate their expression on transcriptional level. However much less is known about human (h)XRN1 function. Data available from human cell lines confirm involvement of hXRN1 in degradation of mRNA, initiator tRNA methionine and some miRNA. The high sequence similarity of XRN1 between yeast and man suggests that also its function should be well conserved for hXRN1. To determine the cytoplasmic transcripts dependent on XRN1 activity we have constructed an auxin-degron system with inducible depletion of XRN1 protein in cell line, combined with subcellular fractionation followed by high-throughput sequencing. The raw data and counts for annotated and non-annotated transcripts resulting from this experiment are provided.
Project description:To study the role of the exonuclease Xrn1 in translational control, we performed ribosome profiling and RNA-seq in Xrn1-depleted cells. By using an auxin-inducible degron, we were able to study immediate effects of Xrn1 depletion in translational control. Therefore, we could overcome experimental limitations associated to stable deletion mutants.
Project description:To study the role of the exonuclease Xrn1 in gene expression dynamics under osmotic stress conditions, we performed RNA-seq in Xrn1-depleted cells. By using an auxin-inducible degron, we were able to study immediate effects of Xrn1 depletion in gene expression dynamics. Therefore, we could overcome experimental limitations associated to stable deletion mutants.
Project description:UPF1 is a multi-domain RNA helicase that constantly monitors the transcriptome by non-specifically binding to mRNAs, dissociating from non-target transcripts, and initiating degradation on selected target RNAs via multiple proposed pathways such as nonsense-mediated decay (NMD). NMD is a translation-coupled mechanism that targets mRNAs harboring a premature stop codon (PTC) for degradation, thereby serving as a quality control and gene regulatory pathway ensuring transcriptome integrity. The UPF1 gene is essential in cultured human cells and previous studies relied mostly on RNA interference to downregulate UPF1. Here we established an auxin-inducible UPF1 degron system in the human colorectal adenocarcinoma cell line HCT116 by first inserting the auxin receptor F-box protein-encoding AtAFB2-mCherry in the AAVS1 locus, followed by tagging UPF1 at the N-terminus with an V5-AID-tag (AID = miniIAA7 = AtIAA7 amino acids 37–104). With this cell lines we performed Ribo-Seq (ribosome footprinting) to assess the effects of UPF1 depletion on translation. To this end, depletion of UPF1 was induced with 500 µM indole-3-acetic acid (IAA) for 12h. As control untreated cells were used.
Project description:UPF1 is a multi-domain RNA helicase that constantly monitors the transcriptome by non-specifically binding to mRNAs, dissociating from non-target transcripts, and initiating degradation on selected target RNAs via multiple proposed pathways such as nonsense-mediated decay (NMD). NMD is a translation-coupled mechanism that targets mRNAs harboring a premature stop codon (PTC) for degradation, thereby serving as a quality control and gene regulatory pathway ensuring transcriptome integrity. The UPF1 gene is essential in cultured human cells and previous studies relied mostly on RNA interference to downregulate UPF1. Here we established an auxin-inducible UPF1 degron system in the human colorectal adenocarcinoma cell line HCT116 by first inserting the auxin receptor F-box protein-encoding AtAFB2-mCherry in the AAVS1 locus, followed by tagging UPF1 at the N-terminus with an V5-AID-tag (AID = miniIAA7 = AtIAA7 amino acids 37–104). With this experiment using rRNA depletion during library preparation, we wanted to explore the time-resolved transcriptome-wide expression changes, especially of non-poly(A) RNAs, upon rapid depletion of UPF1. To this end, depletion of UPF1 was induced with 500 µM indole-3-acetic acid (IAA) for two time periods (12h or 48h). As control, the parental cell line (with AtAFB2-mCherry in the AAVS1 locus) was used.
Project description:UPF1 is a multi-domain RNA helicase that constantly monitors the transcriptome by non-specifically binding to mRNAs, dissociating from non-target transcripts, and initiating degradation on selected target RNAs via multiple proposed pathways such as nonsense-mediated decay (NMD). NMD is a translation-coupled mechanism that targets mRNAs harboring a premature stop codon (PTC) for degradation, thereby serving as a quality control and gene regulatory pathway ensuring transcriptome integrity. The UPF1 gene is essential in cultured human cells and previous studies relied mostly on RNA interference to downregulate UPF1. Here we established an auxin-inducible UPF1 degron system in the human colorectal adenocarcinoma cell line HCT116 by first inserting the auxin receptor F-box protein-encoding AtAFB2-mCherry in the AAVS1 locus, followed by tagging UPF1 at the N-terminus with an V5-AID-tag (AID = miniIAA7 = AtIAA7 amino acids 37–104). With this cell line we wanted to explore the time-resolved transcriptome-wide expression changes including the extent of NMD inhibition upon rapid depletion of UPF1. To this end, depletion of UPF1 was induced with 500 µM indole-3-acetic acid (IAA) for various time periods (0-48h). As controls, the parental cell line (with AtAFB2-mCherry in the AAVS1 locus) or untreated cells were used.
Project description:UPF1 is a multi-domain RNA helicase that constantly monitors the transcriptome by non-specifically binding to mRNAs, dissociating from non-target transcripts, and initiating degradation on selected target RNAs via multiple proposed pathways such as nonsense-mediated decay (NMD). NMD is a translation-coupled mechanism that targets mRNAs harboring a premature stop codon (PTC) for degradation, thereby serving as a quality control and gene regulatory pathway ensuring transcriptome integrity. The UPF1 gene is essential in cultured human cells and previous studies relied mostly on RNA interference to downregulate UPF1. Here we established an auxin-inducible UPF1 degron system in the human colorectal adenocarcinoma cell line HCT116 by first inserting the auxin receptor F-box protein-encoding AtAFB2-mCherry in the AAVS1 locus, followed by tagging UPF1 at the N-terminus or C-terminus with an V5-AID-tag (AID = miniIAA7 = AtIAA7 amino acids 37–104). With these cell lines we wanted to assess the transcriptome-wide expression changes upon rapid depletion of UPF1, estimate the effects of auxin treatment and compare N-terminal versus C-terminal tagging. To this end, depletion of UPF1 was induced with 500 µM indole-3-acetic acid (IAA) for various time periods (0-12h). As controls, the parental cell line (with AtAFB2-mCherry in the AAVS1 locus) or untreated cells were used.
Project description:UPF1 is a multi-domain RNA helicase that constantly monitors the transcriptome by non-specifically binding to mRNAs, dissociating from non-target transcripts, and initiating degradation on selected target RNAs via multiple proposed pathways such as nonsense-mediated decay (NMD). NMD is a translation-coupled mechanism that targets mRNAs harboring a premature stop codon (PTC) for degradation, thereby serving as a quality control and gene regulatory pathway ensuring transcriptome integrity. The UPF1 gene is essential in cultured human cells and previous studies relied mostly on RNA interference to downregulate UPF1. Here we established an auxin-inducible UPF1 degron system in the human colorectal adenocarcinoma cell line HCT116 by first inserting the auxin receptor F-box protein-encoding AtAFB2-mCherry in the AAVS1 locus, followed by tagging UPF1 at the N-terminus with an V5-AID-tag (AID = miniIAA7 = AtIAA7 amino acids 37–104). Using SLAM-Seq and this cell line, we wanted to explore the time-resolved RNA stability changes upon rapid depletion of UPF1. To this end, depletion of UPF1 was induced with 500 µM indole-3-acetic acid (IAA) for various time periods (0h, 12h and 24h) and the cells were labeled with 200 µM 4-thiouridine (4SU) the last 2 hours before harvesting. As controls, the parental cell line (with AtAFB2-mCherry in the AAVS1 locus) or unlabeled cells were used.
Project description:Cullin RING-type E3 ubiquitin ligase SCFTIR1/AFB1-5 and their ubiquitylation targets, AUX/IAAs, sense auxin concentrations in the nucleus. TIR1 binds a surface- exposed degron in AUX/IAAs promoting their ubiquitylation and rapid auxin-regulated proteasomal degradation. Here, we resolved TIR1·auxin·IAA7 and TIR1·auxin·IAA12 complex topology, and show that flexible intrinsically disordered regions (IDRs) cooperatively position AUX/IAAs on TIR1. The AUX/IAA PB1 interaction domain also assists in non-native contacts, affecting AUX/IAA dynamic interaction states. Our results establish a role for IDRs in modulating auxin receptor assemblies. By securing AUX/IAAs on two opposite surfaces of TIR1, IDR diversity supports locally tailored positioning for targeted ubiquitylation, and might provide conformational flexibility for adopting a multiplicity of functional states. We postulate IDRs in distinct members of the AUX/IAA family to be an adaptive signature for protein interaction and initiation region for proteasome recruitment.