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Principal Investigator: MICHAEL FINLEY SUMMERS
Organization: UNIVERSITY OF MARYLAND BALTIMORE COUNTY
Fiscal Year: 2024
Award: $754,566
Funding agency: National Institute of Allergy and Infectious Diseases
7. Project Summary/Abstract
The overall goal of this project is to understand how the HIV-1 5′-leader RNA differentially directs diverse
functions during viral replication, including intracellular trafficking, initiation of translation, recruitment of viral
structural proteins (called Gag), and nucleation of virus assembly. Proposed studies build on our recent
discovery that HIV-1 RNAs are transcribed with one, two or three 5ʹ-guanosines via alternate (heterogeneous)
transcriptional start site usage – a new paradigm in HIV-1 RNA biology. Our studies revealed that 5′-capped
transcripts that begin with a single guanosine (Cap1G) adopt a structure that sequesters the 5′-cap, promotes
dimerization, and exposes Gag binding sites, thereby promoting their functions as genomes (gRNA). In
contrast, 5′-capped transcripts that begin with two or three guanosines (Cap2G/Cap3G) adopt monomeric
structures with an exposed 5′-cap that function in splicing and translation (mRNAs). The central hypothesis
guiding our proposed studies is that cap sequestration enables the HIV-1 gRNA to avoid capture by the cellular
RNA processing and translation machinery, and that a small number of Gag proteins (~2 dozen) are
cooperatively recruited to assembly sites on a well-defined packaging signal (ΨCES) located within the gRNA 5′-
leader. We now aim to identify molecular determinants of alternate transcription initiation and exploit this
knowledge to differentially examine HIV-1 mRNA and gRNA trafficking and interactions in cells, probe RNA
structural changes that occur during virus assembly and maturation, and identify key interactions that promote
Gag:RNA assembly and might be exploited for drug targeting. Preliminary NMR and EM findings suggest that it
should now be possible to determine the 3D structure of the Gag:RNA complex that nucleates HIV-1 virus
particle assembly.
NMR studies of large RNAs and protein-RNA complexes are technically challenging – the average size of
NMR-derived RNA structures in the RNA Structure Database is only 30 nucleotides. But the potential payoff of
the proposed studies is substantial and could ultimately lead not only to a more detailed understanding of how
HIV-1 replicates, but also to the development of new approaches for the treatment of AIDS and to the
engineering of gene delivery vectors with improved packaging efficiencies.
Terms: <3-D><3-D structure><3-Dimensional><3-dimensional structure><3D><3D structure><AIDS><AIDS Virus><Acquired Immune Deficiency><Acquired Immune Deficiency Syndrome><Acquired Immune Deficiency Syndrome Virus><Acquired Immunodeficiency Syndrome><Acquired Immunodeficiency Syndrome Virus><Adopted><Anti-viral Agents><Antimorphic mutation><Behavior><Binding><Binding Sites><Biochemistry><Biological Chemistry><Biology><Biophysics><Cap Binding Protein Complex><Cap Binding Proteins><Cell Body><Cell Communication and Signaling><Cell Signaling><Cell membrane><Cells><Combining Site><Complex><Cytoplasmic Membrane><Development><Dimerization><Dominant Negative><Dominant-Negative Mutant><Dominant-Negative Mutation><Drug Targeting><Electron Microscopy><Elements><Engineered Gene><Engineering><Evolution><Exhibits><Funding><Gene Delivery><Gene Transcription><Genetic><Genetic Transcription><Genome><Goals><Guanosine><Guide RNA><HIV><HIV Genome><HIV-1><HIV-1 genome><HIV-2><HIV-I><HIV-II><HIV1><HIV1 genome><HIV2><HTLV-IV><Human Immunodeficiency Virus Type 1><Human Immunodeficiency Virus Type 2><Human Immunodeficiency Viruses><Human T-Lymphotropic Virus Type IV><Human immunodeficiency virus 1><Human immunodeficiency virus 2><Hybrids><In Vitro><Intracellular Communication and Signaling><Knowledge><LAV-2><LAV-HTLV-III><Lead><Light><Location><Lymphadenopathy-Associated Virus><Macromolecular Structure><Messenger RNA><Modeling><Molecular><Molecular Interaction><Molecular Structure><Monitor><Nature><Non-Polyadenylated RNA><Nuclear Export><Nucleotides><Pb element><Photoradiation><Plasma Membrane><Promoter Regions><Promotor Regions><Protein Dimerization><Proteins><RNA><RNA Binding><RNA Cap-Binding Proteins><RNA Expression><RNA Gene Probes><RNA Gene Products><RNA Probes><RNA Processing><RNA Splicing><RNA bound><Reactive Site><Reporting><Retroviral Antigen gag Protein><Retroviridae><Retroviruses><Ribonucleic Acid><Signal Transduction><Signal Transduction Systems><Signaling><Site><Splicing><Structure><Testing><Transcript><Transcription><Transcription Initiation><Transcription Initiation Site><Transcription Start Site><Translation Initiation><Translations><Viral Gene Products><Viral Gene Proteins><Viral Genome><Viral Proteins><Viral Structural Proteins><Viral gag Proteins><Virion><Virus Assembly><Virus Particle><Virus Replication><Virus-HIV><Virus-Retrovirus><Work><anti-viral compound><anti-viral drugs><anti-viral medication><anti-viral therapeutic><anti-virals><biological signal transduction><biophysical foundation><biophysical principles><biophysical sciences><data base structure><database structure><delivery vector><delivery vehicle><developmental><dimer><drug discovery><experiment><experimental research><experimental study><experiments><gRNA><gag Antigens><gag Gene Products><gag Polyproteins><gag Protein><genetic promoter element><genetic promoter sequence><group specific antigen><heavy metal Pb><heavy metal lead><improved><mRNA><mRNA Cap Binding Proteins><monomer><myristoylation><new therapeutic approach><new therapeutic intervention><new therapeutic strategies><new therapy approaches><new treatment approach><new treatment strategy><novel therapeutic approach><novel therapeutic intervention><novel therapeutic strategies><novel therapy approach><nucleic acid binding protein><particle><plasmalemma><promoter><promoter sequence><promotor><recruit><small molecule><three dimensional><three dimensional structure><trafficking><translation><viral assembly><viral multiplication><viral replication><virus genome><virus multiplication><virus protein>