scholarly journals Gain-of-function genetic screening identifies the antiviral function of TMEM120A via STING activation

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Shuo Li ◽  
Nianchao Qian ◽  
Chao Jiang ◽  
Wenhong Zu ◽  
Anthony Liang ◽  
...  

AbstractZika virus (ZIKV) infection can be associated with neurological pathologies, such as microcephaly in newborns and Guillain-Barre syndrome in adults. Effective therapeutics are currently not available. As such, a comprehensive understanding of virus-host interactions may guide the development of medications for ZIKV. Here we report a human genome-wide overexpression screen to identify host factors that regulate ZIKV infection and find TMEM120A as a ZIKV restriction factor. TMEM120A overexpression significantly inhibits ZIKV replication, while TMEM120A knockdown increases ZIKV infection in cell lines. Moreover, Tmem120a knockout in mice facilitates ZIKV infection in primary mouse embryonic fibroblasts (MEF) cells. Mechanistically, the antiviral activity of TMEM120A is dependent on STING, as TMEM120A interacts with STING, promotes the translocation of STING from the endoplasmic reticulum (ER) to ER-Golgi intermediate compartment (ERGIC) and enhances the phosphorylation of downstream TBK1 and IRF3, resulting in the expression of multiple antiviral cytokines and interferon-stimulated genes. In summary, our gain-of-function screening identifies TMEM120A as a key activator of the antiviral signaling of STING.

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 247-258 ◽  
Author(s):  
Jinghong Li ◽  
Willis X Li

Abstract Overactivation of receptor tyrosine kinases (RTKs) has been linked to tumorigenesis. To understand how a hyperactivated RTK functions differently from wild-type RTK, we conducted a genome-wide systematic survey for genes that are required for signaling by a gain-of-function mutant Drosophila RTK Torso (Tor). We screened chromosomal deficiencies for suppression of a gain-of-function mutation tor (torGOF), which led to the identification of 26 genomic regions that, when in half dosage, suppressed the defects caused by torGOF. Testing of candidate genes in these regions revealed many genes known to be involved in Tor signaling (such as those encoding the Ras-MAPK cassette, adaptor and structural molecules of RTK signaling, and downstream target genes of Tor), confirming the specificity of this genetic screen. Importantly, this screen also identified components of the TGFβ (Dpp) and JAK/STAT pathways as being required for TorGOF signaling. Specifically, we found that reducing the dosage of thickveins (tkv), Mothers against dpp (Mad), or STAT92E (aka marelle), respectively, suppressed torGOF phenotypes. Furthermore, we demonstrate that in torGOF embryos, dpp is ectopically expressed and thus may contribute to the patterning defects. These results demonstrate an essential requirement of noncanonical signaling pathways for a persistently activated RTK to cause pathological defects in an organism.


2019 ◽  
Author(s):  
Aseda Tena ◽  
Yuxiang Zhang ◽  
Nia Kyritsis ◽  
Anne Devorak ◽  
Jeffrey Zurita ◽  
...  

ABSTRACTMild replication stress enhances appearance of dozens of robust recurrent genomic break clusters, termed RDCs, in cultured primary mouse neural stem and progenitor cells (NSPCs). Robust RDCs occur within genes (“RDC-genes”) that are long and have roles in neural cell communications and/or have been implicated in neuropsychiatric diseases or cancer. We sought to develop an in vitro approach to determine whether specific RDC formation is associated with neural development. For this purpose, we adapted a system to induce neural progenitor cell (NPC) development from mouse embryonic stem cell (ESC) lines deficient for XRCC4 plus p53, a genotype that enhances DNA double-strand break (DSB) persistence to enhance detection. We tested for RDCs by our genome wide DSB identification approach that captures DSBs genome-wide via their ability to join to specific genomic Cas9/sgRNA-generated bait DSBs. In XRCC4/p53-deficient ES cells, we detected 7 RDCs, which were in genes, with two RDCs being robust. In contrast, in NPCs derived from these ES cell lines, we detected 29 RDCs, a large fraction of which were robust and associated with long, transcribed neural genes that were also robust RDC-genes in primary NSPCs. These studies suggest that many RDCs present in NSPCs are developmentally influenced to occur in this cell type and indicate that induced development of NPCs from ES cells provides an approach to rapidly elucidate mechanistic aspects of NPC RDC formation.SIGNIFICANCE STATEMENTWe previously discovered a set of long neural genes susceptible to frequent DNA breaks in primary mouse brain progenitor cells. We termed these genes RDC-genes. RDC-gene breakage during brain development might alter neural gene function and contribute to neurological diseases and brain cancer. To provide an approach to characterize the unknown mechanism of neural RDC-gene breakage, we asked whether RDC-genes appear in neural progenitors differentiated from embryonic stem cells in culture. Indeed, robust RDC-genes appeared in neural progenitors differentiated in culture and many overlapped with robust RDC-genes in primary brain progenitors. These studies indicate that in vitro development of neural progenitors provides a model system for elucidating how RDC-genes are formed.


Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1196
Author(s):  
Karsten Krey ◽  
Aleksandra W. Babnis ◽  
Andreas Pichlmair

Viruses pose substantial challenges for society, economy, healthcare systems, and research. Their distinctive pathologies are based on specific interactions with cellular factors. In order to develop new antiviral treatments, it is of central importance to understand how viruses interact with their host and how infected cells react to the virus on a molecular level. Invading viruses are commonly sensed by components of the innate immune system, which is composed of a highly effective yet complex network of proteins that, in most cases, mediate efficient virus inhibition. Central to this process is the activity of interferons and other cytokines that coordinate the antiviral response. So far, numerous methods have been used to identify how viruses interact with cellular processes and revealed that the innate immune response is highly complex and involves interferon-stimulated genes and their binding partners as functional factors. Novel approaches and careful experimental design, combined with large-scale, high-throughput methods and cutting-edge analysis pipelines, have to be utilized to delineate the antiviral innate immune landscape at a global level. In this review, we describe different currently used screening approaches, how they contributed to our knowledge on virus–host interactions, and essential considerations that have to be taken into account when planning such experiments.


2006 ◽  
Vol 17 (11) ◽  
pp. 4675-4685 ◽  
Author(s):  
Linda Yang ◽  
Lei Wang ◽  
Yi Zheng

Recent studies in Cdc42 knockout mouse embryonic stem (ES) cells and ES-derived fibroblastoid cell lines raise concern on a body of literature derived by dominant mutant expression approach in a variety of cell lines implicating mammalian Cdc42 as a key regulator of filopodia induction, directional migration and cell cycle progression. To resolve the physiological function of mammalian Cdc42, we have characterized the Cdc42−/− and Cdc42GAP−/− primary mouse embryonic fibroblasts (MEFs) produced by gene targeting as the Cdc42 loss- or gain-of-activity cell model. The Cdc42−/− cells were defective in filopodia formation stimulated by bradykinin and in dorsal membrane ruffling stimulated by PDGF, whereas the Cdc42GAP−/− cells displayed spontaneous filopodia. The Cdc42 loss- or gain-of-activity cells were defective in adhesion to fibronectin, wound-healing, polarity establishment, and migration toward a serum gradient. These defects were associated with deficiencies of PAK1, GSK3β, myosin light chain, and FAK phosphorylation. Furthermore, Cdc42−/− cells were defective in G1/S-phase transition and survival, correlating with deficient NF-κB transcription and defective JNK, p70 S6K, and ERK1/2 activation. These results demonstrate a different requirement of Cdc42 activity in primary MEFs from ES or ES-derived clonal fibroblastoid cells and suggest that Cdc42 plays cell-type–specific signaling roles.


2017 ◽  
Vol 10 (2) ◽  
pp. 85-93 ◽  
Author(s):  
Keaton M. Crosse ◽  
Ebony A. Monson ◽  
Michael R. Beard ◽  
Karla J. Helbig

The ability of a host to curb a viral infection is heavily reliant on the effectiveness of an initial antiviral innate immune response, resulting in the upregulation of interferon (IFN) and, subsequently, IFN-stimulated genes (ISGs). ISGs serve to mount an antiviral state within a host cell, and although the specific antiviral function of a number of ISGs has been characterized, the function of many of these ISGs remains to be determined. Recent research has uncovered a novel role for a handful of ISGs, some of them directly induced by IFN regulatory factor 3 in the absence of IFN itself. These ISGs, most with potent antiviral activity, are also able to augment varying arms of the innate immune response to viral infection, thereby strengthening this response. This new understanding of the role of ISGs may, in turn, help the recent advancement of novel therapeutics aiming to augment innate signaling pathways in an attempt to control viral infection and pathogenesis.


2015 ◽  
Vol 466 (3) ◽  
pp. 511-524 ◽  
Author(s):  
Katarzyna Blaszczyk ◽  
Adam Olejnik ◽  
Hanna Nowicka ◽  
Lilla Ozgyin ◽  
Yi-Ling Chen ◽  
...  

Evidence is accumulating for the existence of a signal transducer and activator of transcription 2 (STAT2)/interferon regulatory factor 9 (IRF9)-dependent, STAT1-independent interferon alpha (IFNα) signalling pathway. However, no detailed insight exists into the genome-wide transcriptional regulation and the biological implications of STAT2/IRF9-dependent IFNα signalling as compared with interferon-stimulated gene factor 3 (ISGF3). In STAT1-defeicient U3C cells stably overexpressing human STAT2 (hST2-U3C) and STAT1-deficient murine embryonic fibroblast cells stably overexpressing mouse STAT2 (mST2-MS1KO) we observed that the IFNα-induced expression of 2′-5′-oligoadenylate synthase 2 (OAS2) and interferon-induced protein with tetratricopeptide repeats 1 (Ifit1) correlated with the kinetics of STAT2 phosphorylation, and the presence of a STAT2/IRF9 complex requiring STAT2 phosphorylation and the STAT2 transactivation domain. Subsequent microarray analysis of IFNα-treated wild-type (WT) and STAT1 KO cells overexpressing STAT2 extended our observations and identified ∼120 known antiviral ISRE-containing interferon-stimulated genes (ISGs) commonly up-regulated by STAT2/IRF9 and ISGF3. The STAT2/IRF9-directed expression profile of these IFN-stimulated genes (ISGs) was prolonged as compared with the early and transient response mediated by ISGF3. In addition, we identified a group of ‘STAT2/IRF9-specific’ ISGs, whose response to IFNα was ISGF3-independent. Finally, STAT2/IRF9 was able to trigger an antiviral response upon encephalomyocarditis virus (EMCV) and vesicular stomatitis Indiana virus (VSV). Our results further prove that IFNα-activated STAT2/IRF9 induces a prolonged ISGF3-like transcriptome and generates an antiviral response in the absence of STAT1. Moreover, the existence of ‘STAT2/IRF9-specific’ target genes predicts a novel role of STAT2 in IFNα signalling.


2017 ◽  
Author(s):  
Donato Tedesco ◽  
Paul Diehl ◽  
Mikhail Makhanov ◽  
Sylvain Baron ◽  
Alex Chenchik

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii198-ii199
Author(s):  
Clark Chen ◽  
Sanjay Dhawan ◽  
Zhe Zhu ◽  
Pinar Mesci ◽  
Jeremy Rich

Abstract INTRODUCTION Oncolytic virus hold great promise as a platform for glioblastoma therapeutic development. Zika virus (ZIKV) is an oncolytic virus with exquisite selectivity for infecting and killing glioblastoma stem cells (GSCs). Here, we delineate the molecular determinant of this selectivity. METHODS cell-based glioblastoma models, glioblastoma organoid assays, in vivo murine glioblastoma models, ZIKV infectivity assays, gene silencing, ChIP-seq studies. RESULTS In independent models, ZIKV preferentially infected and lysed SOX2+ GSCs. Silencing of SOX2 expression attenuated this preferential infectivity. Of note, ZIKV infection of GSCs was independent of AXL, its putative receptor in normal brain. ChIP-seq experiments revealed that SOX2 bound within the ITGAV locus (encoding the integrin av subunit), and this binding was associated with accumulation of the active chromatin mark H3K27ac. Silencing of SOX2 suppressed ITGAV expression as well as ZIKV infectivity against GSCs, indicating that integrin is required for ZIKV infection. Of integrin b units, only silencing of integrin b5 prevented the killing of GSCs by ZIKV infection, suggesting ZIKV infection required the avb5 integrin. Supporting this hypothesis, blockade of the avb5 integrin substantially reduced ZIKV infection of GSCs in glioblastoma organoid assays and in clinical glioblastoma specimens. Sox2 expression additionally suppress GSC expression of all members of the interferon-stimulated genes (ISG family), thereby suppressing innate anti-viral response to facilitate ZIKV infection. CONCLUSIONS Collectively, our results reveal that ZIKV infection of GSCs is mediated by integrin α vβ 5 leading to SOX2 expression which negatively regulates antiviral immunity thereby facilitating ZIKV infection.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 855-855 ◽  
Author(s):  
Sanada Masashi ◽  
Shih Lee Yung ◽  
Takahiro Suzuki ◽  
Motohiro Kato ◽  
Mamiko Yanagimoto Sakata ◽  
...  

Abstract Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic progenitors characterized by ineffective hematopoiesis and high propensity to leukemias. Although a number of gene targets have been identified, in many MDS cases, particular genetic targets are unknown. In this study, we performed genome-wide profiling of copy number (CN) abnormalities and allelic imbalances in MDS genomes in order to clarify the distribution of LOH (loss of heterozygosity) and to identify their gene targets. We analyzed a total of 171MDS and MDS/MPD specimens, including 7 RA/RARS, 23 RCMD/RCMD-RS, 6 5q-syndrome, 30 RAEB-1, 40 RAEB-2, 4 therapy related-MDS/AML, 5 MDSu, 17 CMML-1, 16 CMML-2, 24 overt AML, using high-density SNP arrays. The data were analyzed by CNAG/AsCNAR software, which enabled allele-specific CN analysis and sensitive LOH detection. MDS showed characteristic CN profiles in SNP array analysis. Of particular interest is the finding of high frequency of CN-neutral LOH (Uniparental disomy,UPD) observed in 51 of 171 (30%) MDS cases. They preferentially involved 1p, 1q, 4q, 7q, 11q, 17p and other chromosomal segments, which were associated with homozygous mutations of both loss-of-function mutations and gain-of function mutations of tumor suppressor genes and cellular oncogenes, including TP53 (17p UPD), AML1/RUNX1 (21q UPD), Nras and cMPL (1p UPD), JAK-2 (9p UPD), and FLT3 (13q UPD). Next we tried to identify a new gene target in 11q UPD, which was most common UPD region in this study and many of these cases were CMML with a normal karyotype. The minimum 11q UPD segment is about 2Mb which existed in 11q23. We sequenced coding exons of c-cbl and detected homozygous mutations in 8 of 9 MDS cases with 11q UPD (CMML=5, RAEB=3, overt leukemia=1), but very rare in cases without 11q UPD (1/162), demonstrating that the mutation is tightly linked to 11q UPD. These mutations were 8 point mutations and 1 micro-deletion, they were accumulated in the linker or RING domain. These c-cbl mutants transformed NIH3T3 in a dominant fashion, in which they were phosphorylated and activate PI3K-Akt pathway. To investigate the functions of these mutants in hematopoietic cells, we introduced these mutants into c-kit(+)Sca1(+)Lin(−) murine bone marrow cells, it prolonged replating capacity of these hematopoietic progenitors, suggesting involvement of aberrant c-cbl functions in the myeloproliferative phenotypes frequently found in 11q-UPD positive cases. In conclusion, UPD is an important mechanism of development of MDS, in which both gain-of-function and loss-of-function mutations are duplicated with exclusion of wild-type allele. Analysis of 11q UPD disclosed novel gain-of-function mutations. Identification of the targets of UPDs in 1q, 4q and 7q should also be important to gain a novel insight into the pathogenesis of MDS.


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