Atomic force microscopy imaging of retroviruses: Human immunodeficiency virus and murine leukemia virus

Abstract

Summary:Retroviruses are membrane-enveloped, RNAcontaining viruses that produce a wide range of threatening diseases in higher animals. Among these are human immunodeficiency virus (HIV), which produces acquired immune deficiency syndrome (AIDS) in humans, and murine leukemia virus (MuLV), which produces leukemias in rodents. We have obtained the first atomic force microscopy (AFM) images of these two retroviruses, both isolated from culture media and emerging from infected cell surfaces. The HIV virions are 127 nm diameter on average, and those of MuLV are 145 nm, although there are wide distributions about the means. The AFM images show the arrangement of the envelope protein, responsible for host cell entry, on the surfaces of both virions. Disruption of the viruses using detergents or physical means allowed us to visualize interior structures, including the outer shells of both MuLV and HIV, the cores of MuLV, and the nucleic acid of HIV complexed with core proteins. Using immunolabeling techniques borrowed from electron microscopy, we were able to demonstrate the binding of gold-labeled antibodies directed against the envelope protein of MuLV. The AFM images are revealing, not only in terms of surface topology, but in terms of interior features as well, and they reveal the eccentricities and uniqueness of individual virus particles rather than yielding the average member of the population. Further application of AFM to viruses associated with other pathologies may ultimately have a significant impact on the diagnosis and treatment of virus-promoted diseases.

Glioma Cells Display Complex Cell Surface Topographies That Resist the Actions of Cytolytic Effector Lymphocytes

“…The cantilevers with oxide sharpened silicon nitride tips were 100 mm long. The images were collected in tapping height mode at frequencies of ∼9.2 kHz with a scanning frequency of 1 Hz (36)(37)(38).…”

Structural and dynamical characterization of tubular HIV‐1 capsid protein assemblies by solid state nuclear magnetic resonance and electron microscopy

“…1 The capsid is believed to be formed by a triangular lattice of CA hexamers, with 12 CA pentamers unevenly distributed at the two ends of the cone to produce a closed shell. 2 Although much progress has been made toward understanding the structure, stability, and assembly of the HIV-1 capsid, through electron microscopy, [3][4][5][6][7][8][9][10] X-ray crystallography, [11][12][13][14][15][16][17][18][19][20] solution nuclear magnetic resonance (NMR), 13,[21][22][23][24][25][26][27] and various biophysical techniques, [28][29][30][31][32][33][34][35][36][37][38][39][40] substantial questions remain regarding the details of intermolecular interactions within and between CA hexamers, the structural variations that permit CA to form both hexamers and pentamers, the driving force for curvature and closure of the CA lattice, and the mechanism and pathway for CA self-assembly. In principle, modern solid state NMR techniques, which can provide sitespecific molecular-level structural information about noncrystalline protein assemblies, [41][...…”

An atomic force microscopy investigation of cyanophage structure

“…The substrates were then either dried and imaged, or washed two to three times with water before analysis. Fixation with glutaraldehyde has been shown in previous studies not, to the resolution of the AFM technique, to perturb the surface structure of viral particles, and poly-l-lysine insures adherence of cells, virus particles, and their components (Kuznetsov et al, 2001(Kuznetsov et al, , 2002(Kuznetsov et al, , 2003(Kuznetsov et al, , 2004(Kuznetsov et al, , 2005a.…”