Journal: mBio
Article Title: Analysis of CA Content and CPSF6 Dependence of Early HIV-1 Replication Complexes in SupT1-R5 Cells
doi: 10.1128/mBio.02501-19
Figure Lengend Snippet: CA content of subviral HIV-1 complexes drops by 50% after fusion and appears to be lost upon nucleoplasmic entry. (A and B) SupT1-R5 cells were incubated with IN.eGFP-carrying HIV-1 NL4-3 virions (2 μU of RT/cell) for 90 min at 16°C. To visualize postfusion HIV-1 complexes, cells were stained with mCLING.Atto647N for 10 min at 16°C. Subsequently, the inoculum was changed for medium with (A) or without (B) mCLING, and cells were transferred to PEI-coated 8-well chamber slides, shifted to 37°C for the indicated time, and fixed with 4% FA–0.2% GA (A) or 4% FA (B). See schematic illustrations of the experiment above fluorescent panels. Samples were immunostained for HIV-1 CA (A and B) and NPC (B). DNA was stained with Hoechst. Confocal sections of cells with enlarged details are shown. In panel A, the arrowhead indicates an mCLING-negative HIV-1 complex inside the cytosol, and arrows indicate HIV-1 virions at the plasma membrane. In panel B, the arrowhead indicates a viral complex at the NPC and arrows point to IN.eGFP-positive complexes in the nucleus. Scale bars, 5 μm. (A and B) The graphs on the right show distribution and intensities of CA signals detected at the indicated time points (TP) for virions at the plasma membrane (PM), subviral complexes in the cytosol (A) or in association with the NPC (B), and for IN.eGFP-labeled complexes inside the nucleus (NU). 3D reconstructions based on z-stacks of cells were analyzed using the Imaris spot detection function applied on the CA and IN.eGFP signals. The median of CA signal intensity in the detected objects was then measured. For intranuclear complexes, only IN.eGFP spots were analyzed. At least 40 cells were analyzed per TP. CA intensities were lower in mCLING-stained samples (A, right), possibly due to a negative effect of the required treatment with 0.2% glutaraldehyde on antigenicity. a.u., arbitrary units; N/A, not applicable. (C) Detection of CA on nuclear HIV-1 complexes after copper-based extraction of infected cells. MDM or SupT1-R5 cells were infected with R5-tropic, IN.eGFP-carrying HIV-1 NL4-3 (6.7 × 10 5 μU of RT/well) at 37°C for 48 h or 5.5 h, respectively. Samples were fixed with 4% FA in PBS, permeabilized with 0.5% Triton X-100, and then extracted using the Click-IT reaction mixture usually employed for copper-catalyzed EdU click labeling. Cells were immunostained for HIV-1 CA and lamin A/C (MDM) (left) or Nup358 (SupT1-R5) (right). Z-sections through the nuclear regions of representative cells are shown. Arrowheads indicate IN.eGFP-positive viral complexes inside the nucleus.
Article Snippet: The human T lymphoblast cell line SupT1-R5 (stably expressing exogenous CCR5 under puromycin selection; a kind gift from R. Doms, University of PA, USA; certified by Eurofins according to DAkkS ISO 9001:2008) was cultivated at 37°C in a humidified incubator with a 5% CO 2 atmosphere, using RPMI 1640 medium with GlutaMAX (ThermoFisher) supplemented with 10% fetal bovine serum (FBS; Merck), 50 U/ml of penicillin, 50 μg/ml of streptomycin (ThermoFisher), and 0.3 μg/ml puromycin (Merck).
Techniques: Incubation, Staining, Labeling, Infection