FIG 4.

The hyphal form of the cho1Δ/Δ mutant has increased exposure of β(1-3)-glucan and binding by the Dectin-1 receptor. Cells were grown as hyphae in human serum. (A) Secondary immunofluorescence analysis was performed with an anti-β(1-3)-glucan antibody. Increased exposure of β(1-3)-glucan in the cho1Δ/Δ mutant and the psd1Δ/Δ psd2Δ/Δ double mutant appears to localize at malformed hyphal tips (indicated by arrows). Staining was performed after formaldehyde fixation. (B) In the absence of formaldehyde fixation, only the cho1Δ/Δ mutant revealed strong staining with either anti-β(1-3)-glucan antibody or sDectin-1–Fc. These probes exhibited overlapping staining patterns in the hyphal cell wall. Top row, bright-field optics; middle row, staining with anti-β(1-3)-glucan antibody and a Cy3 (red)-conjugated secondary antibody; bottom row, staining with sDectin-1–Fc and a Cy2 (green)-conjugated secondary antibody. WT, wild type.