1. A purine loop and the primer binding site are critical for the selective encapsidation of mouse mammary tumor virus genomic RNA by Pr77Gag
- Author
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Lizna M. Ali, Fathima Nuzra Nagoor Pitchai, Serena Bernacchi, Tahir A. Rizvi, Valérie Vivet-Boudou, Roland Marquet, Vineeta N. Pillai, Akhil Chameettachal, Farah Mustafa, Anjana Krishnan, United Arab Emirates University (UAEU), Architecture et Réactivité de l'ARN (ARN), Institut de biologie moléculaire et cellulaire (IBMC), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
AcademicSubjects/SCI00010 ,RNA Splicing ,Gene Products, gag ,Genome, Viral ,Biology ,Vectors in gene therapy ,Real-Time Polymerase Chain Reaction ,03 medical and health sciences ,Mice ,Genetics ,RNA and RNA-protein complexes ,Animals ,[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology ,Guide RNA ,Binding site ,030304 developmental biology ,DNA Primers ,0303 health sciences ,Binding Sites ,Virus Assembly ,030302 biochemistry & molecular biology ,Mouse mammary tumor virus ,RNA ,Group-specific antigen ,biology.organism_classification ,Footprinting ,Dynamic Light Scattering ,3. Good health ,Cell biology ,Mammary Tumor Virus, Mouse ,Purines ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,Nucleic Acid Conformation ,RNA, Viral ,Primer binding site - Abstract
Retroviral RNA genome (gRNA) harbors cis-acting sequences that facilitate its specific packaging from a pool of other viral and cellular RNAs by binding with high-affinity to the viral Gag protein during virus assembly. However, the molecular intricacies involved during selective gRNA packaging are poorly understood. Binding and footprinting assays on mouse mammary tumor virus (MMTV) gRNA with purified Pr77Gag along with in cell gRNA packaging study identified two Pr77Gag binding sites constituting critical, non-redundant packaging signals. These included: a purine loop in a bifurcated stem-loop containing the gRNA dimerization initiation site, and the primer binding site (PBS). Despite these sites being present on both unspliced and spliced RNAs, Pr77Gag specifically bound to unspliced RNA, since only that could adopt the native bifurcated stem–loop structure containing looped purines. These results map minimum structural elements required to initiate MMTV gRNA packaging, distinguishing features that are conserved amongst divergent retroviruses from those perhaps unique to MMTV. Unlike purine-rich motifs frequently associated with packaging signals, direct involvement of PBS in gRNA packaging has not been documented in retroviruses. These results enhance our understanding of retroviral gRNA packaging/assembly, making it not only a target for novel therapeutic interventions, but also development of safer gene therapy vectors., Graphical Abstract Graphical AbstractA single stranded purines (ssPurine) loop in a bifurcated stem-loop structure containing the genomic RNA dimerization initiation site (DIS) hairpin, and the primer binding site (PBS) play a crucial role in the packaging of MMTV genomic RNA by recruiting Pr77Gag precursor polyprotein.
- Published
- 2021