Journal: Cell
Article Title: 3D Correlative Cryo-Structured Illumination Fluorescence and Soft X-ray Microscopy Elucidates Reovirus Intracellular Release Pathway
doi: 10.1016/j.cell.2020.05.051
Figure Lengend Snippet: Tracking reovirus endosomal trafficking and escape (A) Confocal images of U2OS cells expressing late-endosome marker Rab7-eGFP infected with Alexa647-labeled reovirus at indicated times AI. (B and C) Mammalian reovirus (MRV) presence in late endosomes up to 4 h AI (B). Numbers of Gal3--positive endosomes containing MRV for the same period (C) (error bars indicate SD of n = 8 in B and n = 9 in C). (D–K) CryoSIM images of MRV labeled with Alexa488 in mCherry-Gal3 expressing cells showing the concentrations of Gal3 signal in distinct vesicles in red; brightfield and SIM slices respectively at: time 0 mock-uninfected (D and E); 1 h AI (F and G); 2 h AI (H and I); and 4 h AI (J and K). (L) Superposition of SIM processed data of a 4 h AI sample on the 2D X-ray mosaic of the same area and expansion of adjacent FOVs where two adjacent X-ray tomograms were collected and stitched. (M) Expanded region of interest (highlighted purple in L). (N and O) Same as (M) with Gal3 signal in red (N) and reovirus signal in green (O), respectively. (P–R) ROI from 2 h AI with either X-ray grayscale imaging alone or superposed wiith fuorescence signal: single z axis slice from the corresponding tomogram with Gal3 (red) and MRV (green) localization. Multi-vesicular bodies (MVBs) are clearly identifiable with distinct sub-compartments where Gal3 is concentrated (presumably the result of virus-carrying vesicles fusing with virus free late endosomes). Virus-induced carbon-rich substructures are marked by yellow arrows and vesicle areas within MVBs that remain impermeable to Gal3 marked by blue arrows. (S) Overview of the relevant 2 h AI region with both fluorescent signals overlaid.
Article Snippet: U2OS cells (ATCC), or U2OS cells expressing galectin3-mCherry (a kind gift from Harold Wodrich, Bordeaux) were kept in Dulbeccos’ modified Eagle medium (DMEM) (Thermo Fischer Scientific) containing 10% Fetal Bovine Serum (FBS) (Capricorn) and 1% vol/vol of penicillin/streptomycin (Thermo Fischer Scientific) at 37 °C and 5% CO 2 .
Techniques: Expressing, Marker, Infection, Labeling, Imaging, Virus

Figure 6 (A–C) Representative cross-sections from three cells, (A), (B), and (C), in the control population of U2OS cells. Cellular structures are identified with arrows: pink for the gold nanoparticle fiducials (250 nm), purple for mitochondria, red for the nuclear envelope, orange for the endoplasmic reticulum, green for MVBs, light blue for endo/lysosomes, gray for nucleoli. (D) 2D X-ray mosaics of a grid area with reovirus mock-infected U2OS cells with the corresponding SIM fluorescence slice aligned. The areas where higher resolution X-ray data were collected are outlined in blue (two ROIs ) and expanded. (E) Areas of focus in single slices from the 3D tomograms are shown as four overlapping frames with (from left to right): X-ray absorption only, composite of X-ray absorption and red fluorescence, composite of X-ray absorption and green fluorescence and composite of X-ray absorption with both fluorescence signals. (F and G), same as (D) and (E) respectively but for a cell population 1 h after infection. (H and I), same as (D) and (E) respectively but for a cell population 2 h after infection. (J and K), same as (D) and (E) respectively but for a cell population 4 h after infection. Black bars are 1 μm and white bars 10 μm. In (E), spurious signals represent background levels of fluorescence in U2OS cells; both green and red signals are perfectly co-localized, weak (relative to those observed later in the infection) and are not associated with any distinct cytoplasmic structures. In (G), 1h after infection, a number of small but distinct vesicles are both Gal3 and MRV positive while in (I), smaller endosomes have now merged to give rise to MVBs that have distinct compartments infused with Gal3 while others have not been similarly compromised (presumably arising from concatenation of membranes from MRV-free vesicles). Carbon-rich virus-induced domed structures are also seen in single vesicles. In (K), fluorescence is shown in smaller vesicles alongside large vesicle superstructures shown in
Figure 6 M. " width="100%" height="100%">
Journal: Cell
Article Title: 3D Correlative Cryo-Structured Illumination Fluorescence and Soft X-ray Microscopy Elucidates Reovirus Intracellular Release Pathway
doi: 10.1016/j.cell.2020.05.051
Figure Lengend Snippet: SXT and SIM imaging of mock-infected and reovirus-infected U2OS adherent cells, related to Figure 6 (A–C) Representative cross-sections from three cells, (A), (B), and (C), in the control population of U2OS cells. Cellular structures are identified with arrows: pink for the gold nanoparticle fiducials (250 nm), purple for mitochondria, red for the nuclear envelope, orange for the endoplasmic reticulum, green for MVBs, light blue for endo/lysosomes, gray for nucleoli. (D) 2D X-ray mosaics of a grid area with reovirus mock-infected U2OS cells with the corresponding SIM fluorescence slice aligned. The areas where higher resolution X-ray data were collected are outlined in blue (two ROIs ) and expanded. (E) Areas of focus in single slices from the 3D tomograms are shown as four overlapping frames with (from left to right): X-ray absorption only, composite of X-ray absorption and red fluorescence, composite of X-ray absorption and green fluorescence and composite of X-ray absorption with both fluorescence signals. (F and G), same as (D) and (E) respectively but for a cell population 1 h after infection. (H and I), same as (D) and (E) respectively but for a cell population 2 h after infection. (J and K), same as (D) and (E) respectively but for a cell population 4 h after infection. Black bars are 1 μm and white bars 10 μm. In (E), spurious signals represent background levels of fluorescence in U2OS cells; both green and red signals are perfectly co-localized, weak (relative to those observed later in the infection) and are not associated with any distinct cytoplasmic structures. In (G), 1h after infection, a number of small but distinct vesicles are both Gal3 and MRV positive while in (I), smaller endosomes have now merged to give rise to MVBs that have distinct compartments infused with Gal3 while others have not been similarly compromised (presumably arising from concatenation of membranes from MRV-free vesicles). Carbon-rich virus-induced domed structures are also seen in single vesicles. In (K), fluorescence is shown in smaller vesicles alongside large vesicle superstructures shown in Figure 6 M.
Article Snippet: U2OS cells (ATCC), or U2OS cells expressing galectin3-mCherry (a kind gift from Harold Wodrich, Bordeaux) were kept in Dulbeccos’ modified Eagle medium (DMEM) (Thermo Fischer Scientific) containing 10% Fetal Bovine Serum (FBS) (Capricorn) and 1% vol/vol of penicillin/streptomycin (Thermo Fischer Scientific) at 37 °C and 5% CO 2 .
Techniques: Imaging, Infection, Control, Fluorescence, Virus

Pettersen et al., 2004 ). " width="100%" height="100%">
Journal: Cell
Article Title: 3D Correlative Cryo-Structured Illumination Fluorescence and Soft X-ray Microscopy Elucidates Reovirus Intracellular Release Pathway
doi: 10.1016/j.cell.2020.05.051
Figure Lengend Snippet: Correlation of X-ray and fluorescence data in three dimensions using the beamline B24 platform All the data shown here are from a U2OS cell vitrified 4 h AI with high titers of reovirus T3D. Viral components are fluorescently labeled with Alexa488 (green fluorescence), and there is also an endogenously expressed reporter molecule (Galectin-3) that is accumulated in vesicles carrying concentrated reovirus outer capsids and that carries the mCherry fluorophore (red fluorescence). (A) Z slice from the middle of a soft X-ray absorption tomogram (from beamline B24 using the 40 nm objective) of a U2OS cell with the nucleus on the right side of the figure (red arrow; the two leaves of the nuclear membrane are seen clearly) and the cytoplasmic area with a substantial multi-vesicular body/endolysosome (pale blue arrow), containing folded carbon-dense material given the increased X-ray absorption in that structure (pale yellow arrow). In the thinner areas of the distal cytoplasmic region, several holes can be seen as part of the support film used for cell attachment (deep purple arrows). (B) Ortho-slices of (A), showing a representative portion of the volumetric data. (C) 3D rendering of the cryoSIM recorded structures displaying green fluorescence within and around the endolysosome. (D) 3D semi-transparent rendering of all cytoplasmic vesicles that contain red Galectin-3 fluorescence (data also collected on the cryoSIM) and are seen as an indication of viral presence in those vesicles. All images were generated with Chimera ( Pettersen et al., 2004 ).
Article Snippet: U2OS cells (ATCC), or U2OS cells expressing galectin3-mCherry (a kind gift from Harold Wodrich, Bordeaux) were kept in Dulbeccos’ modified Eagle medium (DMEM) (Thermo Fischer Scientific) containing 10% Fetal Bovine Serum (FBS) (Capricorn) and 1% vol/vol of penicillin/streptomycin (Thermo Fischer Scientific) at 37 °C and 5% CO 2 .
Techniques: Fluorescence, Labeling, Membrane, Cell Attachment Assay, Generated
Journal: Cell
Article Title: 3D Correlative Cryo-Structured Illumination Fluorescence and Soft X-ray Microscopy Elucidates Reovirus Intracellular Release Pathway
doi: 10.1016/j.cell.2020.05.051
Figure Lengend Snippet:
Article Snippet: U2OS cells (ATCC), or U2OS cells expressing galectin3-mCherry (a kind gift from Harold Wodrich, Bordeaux) were kept in Dulbeccos’ modified Eagle medium (DMEM) (Thermo Fischer Scientific) containing 10% Fetal Bovine Serum (FBS) (Capricorn) and 1% vol/vol of penicillin/streptomycin (Thermo Fischer Scientific) at 37 °C and 5% CO 2 .
Techniques: Virus, Recombinant, Modification, Infection, Expressing, Plasmid Preparation, Software, Microscopy