Fig. 6

Atp1b1a is required for epidermal cell adhesion.

(a) IF of GFP (a, green), Cdh1 (a′, red) and tight junction marker Tjp1 (a′′, magenta) on a transverse section of the epidermis of a 48 hpf wt embryo expressing peridermal-specific krt4:atp1b1a-gfp, counterstained with DAPI (blue; a′′′ with merged channels). Atp1b1a and Cdh1 are co-localized on the basolateral side of peridermal cells, but are excluded from tight junctions and the apical side of these cells. (b-f). Transverse TEM sections through the medium fin fold of wt and psoriasis mutant embryos raised in isotonic conditions, at 58 hpf. In the mutant epidermis (c,c′), aberrant gaps between peridermal cells (false-colored in green) and underlying keratinocytes (false-colored in red) are apparent when compared to the wt epidermis (b,b′). (d-f) Higher magnifications reveal tight junctions (indicated by arrows) of unaltered morphology in the mutant (e) compared to a wt sibling (d), but less organized lateral regions between peridermal cells (e), and large gaps (*) between peridermal and basal cells (e,f) in the mutant. bc, basal cell; pc, peridermal cell. Scale bars: 1 µm.