Overview of the Nucleic-Acid Binding Properties of the HIV-1 Nucleocapsid Protein in Its Different Maturation States

Guo

et al. 2021

Viruses

The nucleocapsid (NC) protein of human immunodeficiency (HIV) is a small, highly basic protein containing two CCHC zinc-finger motifs, which is cleaved from the NC domain of the Gag polyprotein during virus maturation. We previously reported that recombinant HIV-1 Gag and NCp7 overexpressed in an E. coli host contains two and one zinc ions, respectively, and Gag exhibited much higher selectivity for packaging signal (Psi) and affinity for the stem-loop (SL)-3 of Psi than NCp7. In this study, we prepared NCp7 containing 0 (0NCp7), 1 (NCp7) or 2 (2NCp7) zinc ions, and compared their secondary structure, Psi-selectivity and SL3-affinity. Along with the decrease of the zinc content, less ordered conformations were detected. Compared to NCp7, 2NCp7 exhibited a much higher Psi-selectivity and SL3-affinity, similar to Gag, whereas 0NCp7 exhibited a lower Psi-selectivity and SL3-affinity, similar to the H23&H44K double mutant of NCp7, indicating that the different RNA-binding property of Gag NC domain and the mature NCp7 may be resulted, at least partially, from their different zinc content. This study will be helpful to elucidate the critical roles that zinc played in the viral life cycle, and benefit further investigations of the functional switch from the NC domain of Gag to the mature NCp7.

Section: Discussionmentioning

confidence: 99%

The Zinc Content of HIV-1 NCp7 Affects Its Selectivity for Packaging Signal and Affinity for Stem-Loop 3

Guo

et al. 2021

Viruses

“…The binding properties of the various maturation states of the nucleocapsid protein to nucleic acids vary [74][75][76]. In vitro, these properties induce a massive co-aggregation of recombinant NCp7 and NCp9 with NA templates [57,60,77].…”

Section: Introductionmentioning

confidence: 99%

The HIV-1 ribonucleoprotein dynamically regulates its condensate behavior and drives acceleration of protease activity through membraneless granular phase separation

Lyonnais

Sadiq

Lorca-Oró

et al. 2019

Preprint

Self Cite

A growing number of studies indicate that mRNAs and long ncRNAs can affect protein populations by assembling dynamic ribonucleoprotein (RNP) granules. These phaseseparated molecular 'sponges', stabilized by quinary (transient and weak) interactions, control proteins involved in numerous biological functions. Retroviruses such as HIV-1 form by self-assembly when their genomic RNA (gRNA) traps Gag and GagPol polyprotein precursors. Infectivity requires extracellular budding of the particle followed by maturation, an ordered processing of ~2400 Gag and ~120 GagPol by viral protease (PR). This leads to a condensed gRNA-NCp7 nucleocapsid and a CAp24-self-assembled capsid surrounding the RNP. The choreography by which all of these components dynamically interact during virus maturation is one of the missing milestones to fully depict the HIV life cycle. Here, we describe how HIV-1 has evolved a dynamic RNP granule with successive weak-strong-moderate quinary NC-gRNA networks during the sequential processing of the GagNC domain. We also reveal two palindromic RNA-binding triads on NC, KxxFxxQ and QxxFxxK, that provide quinary NC-gRNA interactions. Consequently, the nucleocapsid complex appears properly aggregated for capsid reassembly and reverse transcription, mandatory processes for viral infectivity. We show that PR is sequestered within this RNP and drives its maturation/condensation within minutes, this process being most effective at the end of budding. We anticipate such findings will stimulate further investigations of quinary interactions and emergent mechanisms in crowded environments throughout the wide and growing array of RNP granules.

Journal of Biological Chemistry

“…Except for Spumaviruses, all retroviral NC’s harbor one or two conserved CCHC domains referred to as zinc fingers (ZF) that bind zinc ion with high affinity ( 19 ). NMR studies on HIV-1 NC revealed that each domain folds into a zinc knuckle ( 20 , 21 ) and that the two are close to each other forming a hydrophobic platform essential for RNA binding ( 22 ). Mutating the conserved C or H residue for S or A caused a drastic decrease in the affinity for Zn 2+ impacting on NCp7 folding and gRNA packaging ( 23 , 24 ).…”

mentioning

confidence: 99%

Quantitative analysis of the formation of nucleoprotein complexes between HIV-1 Gag protein and genomic RNA using transmission electron microscopy

Durand

Seigneuret²,

Burlaud‐Gaillard³

et al. 2022

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