Project description:The UPF3B-dependent branch of the nonsense-mediated RNA decay (NMD) pathway is critical for human cognition. Here, we examined the role of UPF3B in the olfactory system. Single-cell RNA-sequencing (scRNA-seq) analysis demonstrated considerable heterogeneity of olfactory sensory neuron (OSN) cell populations in wild type (WT) mice, and revealed that UPF3B loss influences specific subsets of these cell populations. UPF3B also regulates the expression of a large cadre of anti-microbial genes in OSNs, and promotes the selection of specific olfactory receptor (Olfr) genes for expression in mature OSNs (mOSNs). RNA-seq and Ribotag analyses identified classes of mRNAs expressed and translated at different levels in WT and Upf3b-null mOSNs. Integrating multiple computational approaches, UPF3B-dependent NMD target transcripts that are candidates to mediate the functions of NMD in mOSNs were identified in vivo. Together, our data provides a valuable resource for the olfactory field and insights into the roles of NMD in vivo.
Project description:The overall aim of the experiment is to understand the phenotype of mature mouse olfactory sensory neurons by analyzing the transcripts expressed and enriched in them as compared to the rest of the cell types in the olfactory epithelium (consisting of immature neurons, supporting cells, progenitor cells and cells in lamina propria) and brain ( with out the olfactory bulbs). Comparision with the other cell types in the olfactory epithelium should eliminate the transcripts commonly expressed in the olfactory epithelium and comparision with brain will eliminate the transcripts common to most neurons. Our gene chip data indicates that mature mouse olfactory sensory neurons express 10,000 genes. Mature OSNs specifically contained three clusters of over represented Gene ontology categories: smell, ion transport and cilia. Analysis for the functionally over represented categories among the transcripts with a positive signal in the mature OSNs yielded largely broad categories common to all cells with the exception of chromatin modelling and RNA processing categories. Biological process categories of movement, development and immune response came as under represented categories. Experiment Overall Design: To purify mature olfactory neurons we took advantage of the OMP-GFP mice. OMP(olfactory marker protein) is expressed specifically in mature olfactory and vomeronasal sensory neurons. In the OMP-GFP mice the coding region of OMP is replaced by GFP. We purified OSNs from the rest of the epithelium from these mice by using FACS. . We used the Affymetrix gene chips mouse expression set 430 (consisting of 430A and 430B chips). Our gene chip data is extensively validated by insitu hybridizations.
Project description:Nonsense-mediated mRNA decay (NMD) can occur independently of some NMD factors such as UPF3B. We have performed total RNA-Seq in HCT116 cells under NMD factor knockout (with CRISPR-Cas9) and/or knockdown (with siRNA transfection) conditions to identify mRNA substrates regulated by different NMD factors. We have also performed RIPiT-Seq to identify the footprints of three compositionally distinct EJCs that contain the following pairs of proteins: MAGOH-EIF4A3, UPF3B-EIF4A3 or CASC3-EIF4A3 in WT HCT116 cells.
Project description:Identification of all genes expressed by mouse olfactory sensory neurons; genes expressed in mature neurons, immature neurons, or both were distinguished. Independent validation of enrichment ratio values supported by statistical assessment of error rates was used to build a database of statistical probabilities of the expression of all mRNAs detected in mature neurons, immature neurons, both types of neurons (shared), and the residual population of all other cell types. FACS was used to separate a highly GFP+++ sample enriched in immature neurons, a weakly GFP+ sample slightly enriched in mature neurons, and a GFP- sample that contained all cell types in the olfactory epithelium but depleted of immature neurons.
Project description:The overall aim of the experiment is to understand the phenotype of mature mouse olfactory sensory neurons by analyzing the transcripts expressed and enriched in them as compared to the rest of the cell types in the olfactory epithelium (consisting of immature neurons, supporting cells, progenitor cells and cells in lamina propria) and brain ( with out the olfactory bulbs). Comparision with the other cell types in the olfactory epithelium should eliminate the transcripts commonly expressed in the olfactory epithelium and comparision with brain will eliminate the transcripts common to most neurons. Our gene chip data indicates that mature mouse olfactory sensory neurons express 10,000 genes. Mature OSNs specifically contained three clusters of over represented Gene ontology categories: smell, ion transport and cilia. Analysis for the functionally over represented categories among the transcripts with a positive signal in the mature OSNs yielded largely broad categories common to all cells with the exception of chromatin modelling and RNA processing categories. Biological process categories of movement, development and immune response came as under represented categories. Keywords: cell type comparison
Project description:High-throughput sequencing of individual olfactory sensory neurons from adult male mice.This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
Project description:The paralogous proteins UPF3A and UPF3B are involved in recognizing defective mRNAs that are degraded by nonsense-mediated mRNA decay (NMD). While UPF3B has been demonstrated to support NMD, UPF3A was reported to act either an NMD activator or an NMD inhibitor. Here, we present a comprehensive functional analysis of UPF3A and UPF3B in human cells using overexpression, knockdowns, knockouts (KO) and rescue experiments. Overexpression or knockout of UPF3A did not result in detectable changes in global NMD activity or other specific transcriptome alterations . NMD activity was also virtually unchanged in UPF3B KO cells. In contrast, the co-depletion or co-knockout of UPF3A and UPF3B resulted in a marked NMD inhibition and a global upregulation of PTC-containing transcripts. In rescue experiments UPF3B was fully functional when either UPF2- or EJC binding was impaired . However, the deletion of both interaction sites or one interaction site and a central region of UPF3B impaired its NMD function. Altogether, our work identifies critical functional domains of UPF3B and establishes redundant roles of UPF3A and UPF3B during NMD.