Skip to Main content Skip to Navigation
Theses

Propriétés physiques de capsides virales étudiées à l'échelle du virus unique par microscopie à force atomique : exemples du rétrovirus VIH-1 et du parvovirus AAV

Abstract : Viruses are nanometer size biological parasite, which highjack the cellular machinery of the infected cells to replicate and thereby produce new viruses. A virus consists of a protein capsid, protecting the viral genome, a long polymer of DNA or RNA, and in some cases is surrounded by a lipid envelope. Recent work suggests that the physical properties of viruses are important in order to understand the viral cycle. In order to link the biological behavior of the virus to their physical properties, we used an approach combining AFM imaging and mechanical measurements at the nanometer scale, in connection with the physical modeling of viral capsids. We have developed automated image and force curves analysis tools to quantify the physical properties of viral capsids and the effect of the microenvironment. We have focused on two very different viruses: the HIV-1 retrovirus, responsible for AIDS and the AAV vector used in gene therapy. This work has led to the characterization of the morphological and mechanical properties of virus-like particles and cores of HIV-1 at the single virus level and on populations of hundreds of viruses. Focusing on the effect of the nature of the RNA encapsidated inside the viral particles in cellulo, we have highlighted the structural control of the viral RNA, and more precisely the psi packaging signal, on both HIV-1 VLPs and cores. Finally, we have initiated the study of the effect of reverse transcription (conversion of viral genomic RNA into DNA) within the cores HIV-1 on its stability. The study of parvovirus AAV existing form of several natural variants (serotypes) allowed us to compare the capsid physical properties at thermodynamic equilibrium and out of equilibrium. By varying the microenvironment (temperature and pH), we probed its influence on the stability of the AAV capsid. We have shown in particular that the AAV8 virus is stiffer than AAV9 while thermal stability is reduced, in relation to different biological properties for these two serotypes. In addition, the rigidity of AAV8 capsids decreases in an acidic environment mimicking the late endosome transport, and this results in a higher thermal stability. Finally, we quantified the effect of the length and nature of the confined genome on the thermal stability of AAV capsids.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-01229879
Contributor : Abes Star :  Contact
Submitted on : Tuesday, November 17, 2015 - 12:53:43 PM
Last modification on : Wednesday, November 20, 2019 - 2:39:20 AM
Long-term archiving on: : Thursday, February 18, 2016 - 2:11:12 PM

File

BERNAUD_Julien_2015ENSL1028_Th...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01229879, version 1

Citation

Julien Bernaud. Propriétés physiques de capsides virales étudiées à l'échelle du virus unique par microscopie à force atomique : exemples du rétrovirus VIH-1 et du parvovirus AAV. Biophysique [physics.bio-ph]. Ecole normale supérieure de lyon - ENS LYON, 2015. Français. ⟨NNT : 2015ENSL1028⟩. ⟨tel-01229879⟩

Share

Metrics

Record views

752

Files downloads

477