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Principal Investigator: Zhilong Yang
Organization: TEXAS A&M AGRILIFE RESEARCH
Fiscal Year: 2022
Award: $378,750
Funding agency: National Institute of Allergy and Infectious Diseases
Project Summary
Although smallpox had been eradicated, the chance the virus could arise from unknown stocks or de novo
synthesis remains a credible biothreat. Moreover, other poxviruses cause significant morbidity and mortality in
humans and economically important animals; and poxviruses are widely being developed as vaccine and
protein expression vectors, and anti-cancer agents. Poxvirus gene expression is an arguably irreplaceable
area in elucidating fundamental mechanisms of poxvirus replication and developing poxvirus-based utilities.
Vaccinia virus (VACV) is the prototype poxvirus. VACV post-replicative genes (those expressed after viral DNA
replication) number over 90 and encode mainly virion-associated proteins. They are more efficiently translated
than cellular mRNAs and expressed at high levels. The objective of this project is to elucidate molecular
mechanisms driving selective translation of VACV post-replicative mRNAs, all of which have an unusual
feature—a 5'-poly(A) leader. During the post-replicative stage of VACV infection, the poly(A) leader appears to
confer a translational advantage. The central hypothesis of this project is that the 5'-poly(A) leader coordinates
with specific viral and cellular factors to promote translation of VACV post-replicative mRNAs. Supporting this
hypothesis, D9 and D10, two VACV-encoded decapping enzymes that are known to promote cellular and viral
mRNA degradation, are required for efficient translation of VACV post-replicative mRNAs. Exogenous
expression of D10 in uninfected cells promotes translation of mRNA with a 5'-poly(A) leader. This is striking
given that activation of cellular decapping enzymes causes translation repression. Moreover, La-related protein
4 (LARP4), a cellular poly (A)-binding protein and mRNA translation regulator, is required for VACV post-
replicative protein synthesis. LARP4 is also highly enriched in viral factories, where viral post-replicative mRNA
translation occurs. Three Specific Aims will be carried out to test how these factors promote selectively
translation of VACV post-replicative mRNAs. In Aim 1, the role and molecular determinants of poxvirus
decapping enzymes in promoting viral post-replicative mRNA translation will be defined. In Aim 2, the
mechanisms by which VACV decapping enzymes promote viral post-replicative mRNA translation will be
elucidated. In Aim 3, how LARP4 regulates VACV post-replicative mRNA translation will be determined. The
results will provide an integrated new paradigm illustrating how an intrinsic sequence in viral transcripts,
specific viral and cellular factors orchestrate selective translation of VACV post-replicative mRNAs, and in turn,
VACV replication. The information can be used to tune or block poxvirus replication and improve the efficacy of
VACV vectors used in vaccine and oncolytic cancer therapy. Moreover, these findings can provide knowledge
for understanding fundamental mechanisms of eukaryotic translation.
Terms: <7-methylguanosine><Animals><Anti-Cancer Agents><Antineoplastic Agents><Antineoplastic Drugs><Antineoplastics><Area><Automobile Driving><Cancer Drug><Cancer Treatment><Cell Body><Cells><DNA Replication><DNA Synthesis><DNA biosynthesis><Development><Gene Action Regulation><Gene Expression><Gene Expression Regulation><Gene Regulation><Gene Regulation Process><Genes><Genetic Translation><Human><Individual><Initiation Factors><Knowledge><Malignant Neoplasm Therapy><Malignant Neoplasm Treatment><Mediating><Messenger RNA><Modern Man><Molecular><Morbidity><Morbidity - disease rate><Neoplastic Disease Chemotherapeutic Agents><Oncolytic><Outcome><Peptide Initiation Factors><Plasmids><Poly A><Poly(A)+ mRNA Binding Protein><Poly(A)-Binding Proteins><Poly(rA)><Poxviridae><Poxvirus officinale><Poxviruses><Protein Biosynthesis><Proteins><Repression><Ribosomal Peptide Biosynthesis><Ribosomal Protein Biosynthesis><Ribosomal Protein Synthesis><Ribosomal Proteins><Role><Site><Smallpox><Testing><Transcript><Translating><Translation Initiation><Translation Initiation Factor><Translational Initiation Factor><Translations><Tumor-Specific Treatment Agents><Vaccines><Vaccinia virus><Variola><Viral><Viral Diseases><Virion><Virus><Virus Diseases><Virus Particle><Virus Replication><anti-cancer drug><anti-cancer therapy><anticancer agent><anticancer drug><anticancer therapy><base><bio-threat><biothreat><cancer therapy><cancer-directed therapy><decapping enzyme><develop a vaccine><develop vaccines><development of a vaccine><developmental><driving><experiment><experimental research><experimental study><expression vector><improved><mRNA><mRNA Decay><mRNA Degradation><mRNA Transcript Degradation><mRNA Translation><mortality><mutant><plasmid vaccine><polyadenylate><pox virus><poxvirus vectors><protein expression><protein synthesis><prototype><recombinant vaccinia virus><recruit><small pox><social role><translation factor><vaccine development><vaccinia vector><vaccinia virus vector><variola major><vector vaccine><viral DNA><viral infection><viral multiplication><viral replication><virus DNA><virus infection><virus multiplication><virus-induced disease>