Spatially distinct collagen IV turnover. (A) Time-lapse images of eGFP-COL4A2 FRAP experiments. Confocal single-color images (upper) and pseudocolor images (lower) show the BM of a developing hair follicle in explants that were photobleached in the tip (blue arrowheads), lower stalk (orange arrowheads), and follicular–interfollicular junction (gray arrowheads) regions before and after photobleaching at selected recovery times. Scale bar: 20 μm. (B) Line graph of the normalized fluorescence recovery of eGFP-COL4A2 over 4 h (n = 6 hair follicles, each from a separate explant in an independent experiment). The cyan lines are simple linear regressions for the data derived from each region. Values: means ± SD. (C) Comparison of the recovery rates of eGFP-COL4A2 signals between BMs in different regions. The normalized mean intensity values of eGFP-COL4A2 fluorescence in the bleached regions from the FRAP experiments at 3 h and 30 min, as shown in Fig. 3 B, were used. Values: means ± SD. One-way ANOVA with Tukey’s post-hoc tests was used. Data distribution was assumed to be normal, but this was not formally tested. (D) Maximum projection images of mKikGR-COL4A2 in developing hair follicles in embryonic skin explants from mKikGR-Col4a2 mice at the indicated times after photoconversion. Scale bar: 20 μm.