Fig 2: Luminal epithelial populations display spatial and morphological heterogeneity.(A) H and E and IF of serial sections from the DP and LP, showing expression of proximal (Ppp1r1b) and distal (Tgm4, Msmb) markers; note apparent differences in the boundary regions of the two lobes. (B) Detection of distally localized LumP cells (arrows) in all four lobes; these are most abundant in the VP. (C) Scanning electron micrographs of the boundary region of the AP; central low-power image is flanked by high-power images of boxed regions. Red arrow, mitochondria; black arrow, membrane interdigitation; blue arrow, Golgi apparatus; green arrow, rough endoplasmic reticulum. (D) Identification of the periurethral region. Cells in the periurethral region generally express Ly6d, Ck7, Aqp3, and Ppp1r1b; notably, Cldn10-expressing LumP cells decrease approaching the periurethral region (E) Lineage-marking in Nkx3.1Cre/+; R26R-YFP mice (n = 3) shows widespread YFP expression in the periurethral, proximal, and distal AP; small patches remain unrecombined and lack YFP (arrows). Scale bars in (A,B,D,E) indicate 50 µm; scale bars in (C) indicate 2 µm.