Fig. 4. DG^-/- cell monolayers failed to bind endogenous laminin or exogenous laminin-111-FITC. (A) Vertically paired immunofluorescent images of DG^+/+ and partial-DG^-/- MEpG cell populations co-stained using laminin and C-terminal ß-DG antibodies, followed by Rhodamine- and FITC-labelled secondary antibodies, respectively, all in the presence of Tween-20 (images above line). Arrows point to a DG^-/- cell that retained staining for intracellular but not cell-surface laminin. Cells immunostained for laminin in the absence of Tween-20 are shown below the line, with corresponding phase images. (B) Immunofluorescent images of DG^+/+ and partial-DG^-/- cell populations treated with 10 nM exogenously added laminin-111-FITC for 4 hours. Samples were co-stained using C-terminal ß-DG antibody and Rhodamine-labeled secondary antibody. Corresponding phase images are shown in the bottom panel. Arrows point to a DG^-/- cell lacking laminin-111-FITC staining. (C) Immunofluorescent images of DG^+/+ cells treated with 10 nM exogenous laminin-111-FITC for 24 hours in the absence or presence of 6 and/or ß1 integrin function blocking antibodies (upper panel). Corresponding phase images are shown in the bottom panel. Insets show cells incubated only with 10 nM AEBSF-treated laminin-111 for 24 hours, followed by immunostaining for laminin as described for upper images in A. Bars, 10 µm.