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Principal Investigator: Derek Walsh
Organization: NORTHWESTERN UNIVERSITY AT CHICAGO
Fiscal Year: 2021
Award: $395,000
Funding agency: National Institute of Allergy and Infectious Diseases
PROJECT SUMMARY
Humans have a profound, double-edged relationship with poxviruses. On one hand, the devastating effects of
smallpox are unparalleled by any other pathogen in recorded history, and its eradication is a milestone in
modern medicine. On the other, poxviruses are now used as highly effective gene therapy and vaccine vectors
as well as oncolytics in the treatment of cancer. Moreover, molluscum contagiosum is widespread and causes
prolonged, untreatable lesions, while emerging poxviruses are a serious concern. Indeed, smallpox evolved
from a rodent Taterapox virus and zoonotic poxvirus infections resulting in human-to-human transmission are
being reported at an increasing frequency. In some cases smallpox vaccination does not provide protection,
while live smallpox vaccines such as Vaccinia Virus (VacV) pose serious, life-threatening complications for
many individuals. As such, whether it be infection by existing or future poxviruses, zoonotic infections or
complications from therapeutic vectors, it is important to understand how these unusual pathogens replicate.
Unlike most other double-stranded DNA viruses, poxviruses replicate in the cytoplasm of infected cells within
viral factories (VFs). Encoding >200 genes that include their own polymerases, transcription factors and redox
system, poxviruses exhibit remarkable self-sufficiency. Despite this, poxviruses remain absolutely dependent
on gaining access to host ribosomes in order to synthesize viral proteins, representing an exploitable
weakness. Indeed, we have shown previously that VacV activates the host cap-dependent translation
machinery and that this can be targeted using small molecules to suppress virus replication without
cytotoxicity. Our preliminary data identifies a series of new and unexpected modifications induced by VacV.
This includes a viral protein that remodels mammalian Target of Rapamycin (mTOR), a key regulator of
ribosome recruitment and host immune responses, displacing regulatory subunits to render mTOR
constitutively active and beyond host control. In addition, mass spectrometry and dual-color live cell imaging
revealed that VacV phosphorylates the small ribosomal subunit, RACK1 at unique sites not induced by other
viruses or stimuli, and recruits RACK1 to VFs as they form. Moreover, we find that this modification is required
for selective synthesis of late VacV proteins, but not proteins of other viruses, and is induced by a VacV
kinase. Finally, proteomic analysis of ribosome complexes isolated from primary human cells further revealed
that VacV induces highly selective modifications to other ribosomal proteins and to the subunit composition of
ribosomes themselves. Our data suggests that this “ribosome specialization” is important for poxvirus protein
synthesis, and is dispensable to the host. Understanding how these modifications facilitate VacV protein
synthesis will provide important insights into fundamental aspects of poxvirus biology as well as mechanisms
of selective mRNA translation. In addition, identifying factors involved in selective viral versus host protein
synthesis has the potential to uncover new therapeutic targets and approaches to combat poxvirus infection.
Terms: <Affect><Africa><Anti-Viral Response><Antiviral Response><Attenuated Vaccines><Basal Transcription Factor><Basal transcription factor genes><Binding><Biology><Birds of Prey><Cancer Treatment><Cell Body><Cell Communication and Signaling><Cell Signaling><Cells><Clinical><Color><Complex><Cow Pox Virus><Cowpox virus><Cytoplasm><DNA Replication><DNA Synthesis><DNA Therapy><DNA Viruses><DNA biosynthesis><Dangerousness><Data><Dependence><Development><Disease Outbreaks><Double Stranded DNA Virus><Elements><Eukaryotic Initiation Factors><Eukaryotic Peptide Initiation Factors><Eukaryotic Translation Initiation Factors><Event><Evolution><Exhibits><FK506 Binding Protein 12-Rapamycin Associated Protein 1><FKBP12 Rapamycin Complex Associated Protein 1><FRAP1><FRAP1 gene><FRAP2><Face><Fear><Frequencies><Fright><Future><Gene Transcription><Gene Transfer Clinical><General Transcription Factor Gene><General Transcription Factors><Genes><Genetic Intervention><Genetic Transcription><Genetic Translation><Genome><Head><Health><Herpesviridae><Herpesviruses><History><Human><Immune response><Immunological response><Individual><Infection><Intracellular Communication and Signaling><Kinases><Laboratories><Lesion><Life><Live-attenuated Vaccine><Lytotoxicity><Malignant Neoplasm Therapy><Malignant Neoplasm Treatment><Mass Photometry/Spectrum Analysis><Mass Spectrometry><Mass Spectroscopy><Mass Spectrum><Mass Spectrum Analyses><Mass Spectrum Analysis><Mechanistic Target of Rapamycin><Mediating><Messenger RNA><Metabolic><Minor><Modern Man><Modern Medicine><Modernization><Modification><Molecular Interaction><Molluscum Contagiosum><Monkey Pox><Monkeypox><Oncolytic><Outbreaks><Oxidation-Reduction><P variolae><P. variolae><P.variolae><Phosphorylation><Phosphotransferase Gene><Phosphotransferases><Polymerase><Population><Poxviridae><Poxviridae Infections><Poxviridae disease><Poxvirus Infections><Poxvirus officinale><Poxvirus variolae><Poxviruses><Protein Biosynthesis><Protein Phosphorylation><Proteins><Proteomics><RAFT1><RNA Expression><Raptors><Recording of previous events><Recycling><Redox><Refractory><Regulation><Regulatory Pathway><Reporting><Research><Ribosomal Peptide Biosynthesis><Ribosomal Protein Biosynthesis><Ribosomal Protein Synthesis><Ribosomal Proteins><Ribosomes><Rodent><Rodentia><Rodents Mammals><Role><Series><Signal Transduction><Signal Transduction Systems><Signaling><Site><Smallpox><Smallpox Vaccine><Smallpox virus><Stimulus><Structure><System><Taterapox virus><Therapeutic><Transcription><Transcription Factor Proto-Oncogene><Transcription factor genes><Translating><Translations><Transmission><Transphosphorylases><Vaccinated><Vaccination><Vaccines><Vaccinia virus><Variola><Variola major virus><Variola virus><Viral><Viral Diseases><Viral Gene Products><Viral Gene Proteins><Viral Proteins><Virus><Virus Diseases><Virus Replication><Work><Zoonoses><Zoonotic><Zoonotic Infection><anti-cancer therapy><anticancer therapy><base><biological signal transduction><cancer therapy><cancer-directed therapy><combat><cytotoxicity><developmental><dsDNA Virus><faces><facial><gene therapy><gene-based therapy><genetic therapy><genomic therapy><herpes virus><host response><immune system response><immunoresponse><inhibitor><inhibitor/antagonist><insight><live cell image><live cell imaging><live cellular image><live cellular imaging><live vaccine><live vaccines><mRNA><mRNA Translation><mTOR><mammalian target of rapamycin><new approaches><new drug target><new druggable target><new pharmacotherapy target><new therapeutic target><new therapy target><novel approaches><novel drug target><novel druggable target><novel pharmacotherapy target><novel strategies><novel strategy><novel therapeutic target><novel therapy target><oxidation reduction reaction><pathogen><plasmid vaccine><pox virus><protein synthesis><prototype><recombinant vaccinia virus><recruit><sensor><small molecule><small pox><small pox vaccine><small pox virus><social role><therapeutic agent development><therapeutic development><transcription factor><translation factor><transmission process><variola major><vector><vector vaccine><viral infection><viral multiplication><viral replication><virus infection><virus multiplication><virus protein><virus-induced disease>