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Principal Investigator: Ian J Mohr
Organization: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
Fiscal Year: 2023
Award: $436,140
Funding agency: National Institute of General Medical Sciences
7. PROJECT SUMMARY / ABSTRACT
Regulation of gene expression at the level of translation allows cells and organisms to respond swiftly to
physiological stress and changing environments. Indeed, differential translation of capped, polyadenylated
mRNAs by eukaryotic ribosomes plays a critical role in biological processes vital for human health, including
normal cell growth, differentiation, development, learning and memory, and responses to physiological stress
including virus infection. Viral model systems have proven useful in elaborating cellular translational control
strategies because their replication is absolutely reliant upon virus mRNA translation by host ribosomes. Here,
we utilize a herpesvirus family member, human cytomegalovirus (HCMV), to probe the complex circuitry
regulating mRNA translation. Although innocuous in healthy individuals, HCMV is a widespread, opportunistic
pathogen responsible for severe disease among the immunocompromised, including organ transplant
recipients and AIDS patients. In addition, congenital HCMV infection is the leading viral cause of birth defects
in newborns. Our long-term overall objective is to understand the mechanism(s) through which HCMV
manipulates the cellular translational machinery to control viral replication. A fundamental step
regulating protein synthesis in HCMV-infected cells involves ribosome recruitment to the 5'-end of m7G-capped
virus and host mRNAs. This typically involves 5'-cap-recognition by a translation initiation factor complex
containing the cap-binding protein eIF4E followed by loading the eIF3-bound 40S ribosome. Unexpectedly, an
alternative form of 40S ribosome loading relying upon cap-recognition by a specific eIF3 subunit, eIF3d, has
been described that bypasses the need for eIF4E and is distinctly regulated. Preliminary results establish that
targeting eIF3d selectively inhibited HCMV replication, reduced polyribosome abundance and interfered with
expression of essential virus late genes and a host gene expression signature indicative of chronic ER stress
that fosters HCMV reproduction. Based on our preliminary results, we hypothesize that eIF3d-dependent cap-
recognition is hijacked to exploit virus-induced ER-stress and switching between eIF4E and eIF3d-responsive
translation differentially tunes virus and host gene expression in infected cells. This hypothesis is tested in
three specific aims designed to: i) determine how HCMV infection impacts eIF3d accumulation and sub-cellular
distribution; ii) define the mechanism whereby eIF3d selectively shapes the gene expression landscape in
HCMV-infected cells; and iii) decipher how eIF3d activity is regulated in HCMV-infected cells. The project is
impactful because how non-canonical translation initiation mechanisms involving eIF3d regulate differential
mRNA translation during stress responses like virus infection remains largely unknown and represents a
significant knowledge gap poised to reveal new biology and therapeutic opportunities for interfering with virus
replication or vaccine development. Furthermore, it will provide insight into fundamental translational control
mechanisms important in human diseases, like cancer and diabetes, where protein production is dysregulated.
Terms: <0-4 weeks old><AIDS><Acquired Immune Deficiency><Acquired Immune Deficiency Syndrome><Acquired Immuno-Deficiency Syndrome><Acquired Immunodeficiency Syndrome><Acquired Immunologic Deficiency Syndrome><Attenuated><Binding><Biologic Models><Biological Function><Biological Models><Biological Process><Biology><Birth Defects><Bone Marrow><Bone Marrow Reticuloendothelial System><Bypass><CMV><CMV infection><Cancers><Cap Binding Proteins><Cell Body><Cells><Cellular Expansion><Cellular Growth><Chronic><Complex><Congenital Abnormality><Congenital Anatomic Abnormality><Congenital Anatomical Abnormality><Congenital Defects><Congenital Deformity><Congenital Malformation><Cytomegalic Inclusion Disease><Cytomegalovirus><Cytomegalovirus Infections><Data><Development><Diabetes Mellitus><Disease><Disorder><ER stress><Environment><Expression Signature><FK506 Binding Protein 12-Rapamycin Associated Protein 1><FKBP12 Rapamycin Complex Associated Protein 1><FRAP1><FRAP1 gene><FRAP2><Family member><Fostering><Gene Action Regulation><Gene Expression><Gene Expression Profile><Gene Expression Regulation><Gene Regulation><Gene Regulation Process><Genes><HCMV><Health><Herpesviridae><Herpesviruses><Human><Immune response><Immune system><Immunocompromised><Immunocompromised Host><Immunocompromised Patient><Immunological response><Immunosuppressed Host><Inclusion Disease><Individual><Infection><Initiation Factors><Investigation><Knowledge><Learning><Malignant Neoplasms><Malignant Tumor><Mechanistic Target of Rapamycin><Memory><Messenger RNA><Model System><Modeling><Modern Man><Molecular><Molecular Interaction><Newborn Infant><Newborns><Normal Cell><Organism><Patients><Peptide Initiation Factors><Phosphorylation><Physiologic><Physiological><Play><Poly(A)+ mRNA><Polyadenylated mRNA><Polyadenylation Pathway><Polyribosomes><Polysomes><Production><Protein Biosynthesis><Protein Phosphorylation><Proteins><RAFT1><RNA Cap-Binding Proteins><Regulation><Reproduction><Ribosomal Peptide Biosynthesis><Ribosomal Protein Biosynthesis><Ribosomal Protein Synthesis><Ribosomes><Role><Salivary Gland Virus Disease><Salivary Gland Viruses><Shapes><Solid><Stress><Testing><Therapeutic><Therapeutic Intervention><Translation Initiation><Translation Initiation Factor><Translational Initiation Factor><Translations><Transplant Recipients><Viral><Viral Diseases><Virus><Virus Diseases><Virus Replication><attenuate><attenuates><biological adaptation to stress><cell growth><cytomegalovirus group><design><designing><develop a vaccine><develop vaccines><development of a vaccine><developmental><diabetes><endoplasmic reticulum stress><gene expression pattern><gene expression signature><herpes virus><host response><human disease><immune system response><immunoresponse><immunosuppressed patient><insight><intervention therapy><living system><mRNA><mRNA Cap Binding Proteins><mRNA Translation><mRNA polyadenylation><mTOR><malignancy><mammalian target of rapamycin><mutant><neoplasm/cancer><newborn child><newborn children><opportunistic pathogen><organ transplant recipient><polyadenylated messenger RNA><protein synthesis><reaction; crisis><recruit><response><social role><stress response><stress; reaction><transcriptional profile><transcriptional signature><translation><transplant patient><vaccine development><vaccine strategy><viral infection><viral multiplication><viral replication><virus infection><virus multiplication><virus-induced disease>