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Principal Investigator: James M Burke
Organization: UNIVERSITY OF FLORIDA
Fiscal Year: 2024
Award: $483,000
Funding agency: National Institute of General Medical Sciences
PROJECT SUMMARY
Ribonuclease L (RNase L) is a key component of the mammalian innate antiviral response. For decades, RNase
L was presumed to reduce viral protein synthesis by cleaving ribosomes to arrest translation. However, we and others
recently demonstrated that RNase L-cleaved ribosomes are translation-competent, and that pathogenic viruses can
synthesize proteins despite activating RNase L. These observations have revealed a significant gap in knowledge
regarding how RNase L functions and how viruses evade it. We have demonstrated that RNase L rapidly degrades nearly
all cellular mRNAs upon activation. This activity regulates three cellular processes that have expanded our understanding
of RNase L and that have elucidated how pathogenic viruses evade and potentially hijack RNase L functions. First,
RNase L reprograms translation to an antiviral state by degrading constitutively expressed cellular mRNAs while
sparing host mRNAs encoding antiviral proteins (e.g., type I interferons), which permits antiviral protein synthesis.
Importantly, the mRNAs encoded by several pathogenic viruses (e.g., dengue virus) similarly evade RNase L-mediated
mRNA decay, thus permitting viral protein synthesis. This observation has elucidated how pathogenic viruses synthesize
proteins despite activating RNase L. This application proposes to characterize the RNase L-mediated mRNA decay
pathway and determine how host and viral mRNAs evade it. Second, RNase L activation triggers the inhibition of nuclear
mRNA export. This is a critical antiviral mechanism that antagonizes influenza A virus protein synthesis, but it also
downregulates the expression of host antiviral proteins (e.g., type I interferons). Importantly, pathogenic viruses (e.g.,
dengue virus) activate this RNase L-dependent pathway, resulting in sequestration of host antiviral mRNAs in the
nucleus. This observation suggests that viruses potentially hijack this function of RNase L to limit host antiviral protein
production. This application aims to determine how RNase L inhibits mRNA export, the breadth of viruses it antagonizes,
how it impacts host antiviral gene expression during pathogenic viral infections. Third, RNase L regulates the assembly
of cytoplasmic antiviral ribonucleoprotein complexes. Specifically, RNase L inhibits the assembly of stress granules and
promotes the assembly of an alternative stress granule-like ribonucleoprotein complex termed RNase L-dependent body.
RNase L-dependent bodies are the predominant antiviral granule assembled in response to SARS-CoV-2 or dengue virus
infection, yet their function is completely unknown. This application aims to determine the function of antiviral stress
granules and RNase L-dependent bodies and to determine how their regulation by RNase L alters the antiviral response.
Understanding the mechanisms and functions of these cellular processes will advance our understanding of the
OAS/RNase L pathway, innate immune antiviral gene induction, and virology. Moreover, it will promote general
medicine by broadly characterizing fundamental cellular, molecular, and RNA biology that is relevant to non-infectious
diseases, including autoimmune diseases, neurodegeneration, and cancer. Lastly, the proposed research will support the
development of promising antiviral, immunomodulatory, and anticancer therapies based on RNase L biology.
Terms: <2019 novel corona virus><2019 novel coronavirus><2019-nCoV><Acceleration><Anti-viral Response><Autoimmune Diseases><Biology><Breakbone Fever Virus><COVID-19 virus><COVID19 virus><Cancer Treatment><Cancers><Cell Function><Cell Nucleus><Cell Physiology><Cell Process><Cellular Function><Cellular Physiology><Cellular Process><CoV-2><CoV2><Complex><Cytoplasm><Cytoplasmic Granules><DENV><DENV infection><Dengue Infection><Dengue Virus><Dengue fever virus><Dengue virus infection><Development><Disease><Disorder><Gene Expression><Immune><Immunes><Immunomodulation><Influenza A><Influenza A virus><Influenza Viruses Type A><Influenzavirus A><Interferon Type I><Knowledge><Malignant Neoplasm Therapy><Malignant Neoplasm Treatment><Malignant Neoplasms><Malignant Tumor><Mediating><Medicine><Messenger RNA><Molecular><Nerve Degeneration><Neuron Degeneration><Non-Polyadenylated RNA><Nuclear><Nucleus><Orthomyxovirus Type A><Pathogenicity><Pathway interactions><Process><Production><Protein Biosynthesis><RNA><RNA Gene Products><RNA Nucleases><RNase><Regulation><Research><Ribonuclease Family Protein><Ribonucleases><Ribonucleic Acid><Ribonucleoproteins><Ribosomal Peptide Biosynthesis><Ribosomal Protein Biosynthesis><Ribosomal Protein Synthesis><Ribosomes><SARS corona virus 2><SARS-CO-V2><SARS-COVID-2><SARS-CoV-2><SARS-CoV2><SARS-associated corona virus 2><SARS-associated coronavirus 2><SARS-coronavirus-2><SARS-related corona virus 2><SARS-related coronavirus 2><SARSCoV2><Severe Acute Respiratory Coronavirus 2><Severe Acute Respiratory Distress Syndrome CoV 2><Severe Acute Respiratory Distress Syndrome Corona Virus 2><Severe Acute Respiratory Distress Syndrome Coronavirus 2><Severe Acute Respiratory Syndrome CoV 2><Severe Acute Respiratory Syndrome-associated coronavirus 2><Severe Acute Respiratory Syndrome-related coronavirus 2><Severe acute respiratory syndrome associated corona virus 2><Severe acute respiratory syndrome coronavirus 2><Severe acute respiratory syndrome related corona virus 2><Subcellular Process><Translations><Type A Influenza><Viral><Viral Diseases><Viral Gene Products><Viral Gene Proteins><Viral Genes><Viral Proteins><Virus><Virus Diseases><Wuhan coronavirus><anti-cancer therapy><autoimmune condition><autoimmune disorder><autoimmunity disease><cancer therapy><cancer-directed therapy><coronavirus disease 2019 virus><coronavirus disease-19 virus><dengue viral infection><developmental><gene induction><granule><hCoV19><immune modulation><immune regulation><immunologic reactivity control><immunomodulatory><immunoregulation><immunoregulatory><induction of genes><mRNA><mRNA Decay><mRNA Export><malignancy><nCoV2><neoplasm/cancer><neural degeneration><neurodegeneration><neurodegenerative><neurological degeneration><neuronal degeneration><pathogenic virus><pathway><programs><protein synthesis><response><stress granule><translation><viral infection><viral pathogen><virology><virus infection><virus pathogen><virus protein><virus-induced disease>