Fig. 5. Dual imaging of fibronectin and LTBP1 in a day-2 FRC culture. Still image frames taken at the start of time-lapse imaging in a day 2 FRC culture using fluorescent probes for fibronectin (FN, green) and LTBP1 (red). Note that the fibrillar staining for LTBP1 is predominantly colocalized with fibronectin, as indicated by the yellow areas in the merged image. However, the LTBP1 probe also gives some staining of the cells. A movie corresponding to these images is available as Movie 5 in supplementary material and shows that both fibrillar networks undergo continual stretching and contraction in response to cell movement. Bar, 100 µm.