Figure 5

Id4 expression is associated with proliferation (Ki67), apoptosis (TUNEL) and proliferative markers (Myc, Id1 and Sox9). A: Increased proliferation represented by high Ki67 immuno-staining was observed in Id4-/-. Cells at the tips of the finger like projections stained more strongly with Ki67 as compared to those near the basement membrane (inset in Panel A). Panel B: High Ki67 was observed only in a few cells in the glandular epithelial cells of the wild type (Id4+/+) prostate (black arrowheads). Panels C- F: High nuclear Myc (C) and Id1 (E, and inset) expression was observed in the Id4-/- epithelial cells as compared to wild type littermates (D and F respectively). Panels G and H: Nuclear Sox9 expression was absent in the wild type (Id4+/+, Panel H) but high nuclear Sox9 expression was observed in the Id4-/- glandular epithelial cells of the prostate (Panel G). Panels I and J: TUNEL assay demonstrated increased apoptosis in in Id4 -/- mice prostates (Panel I and inset, Brown staining) as compared to the wild type littermates (Panel D and inset). The graph in panel J represents average number of TUNEL positive cells per field. The TUNEL positive cells were counted in five fields (at 400×) on three different tissue samples. Average number of TUNEL positive cells per field represented as mean + SEM in Id4-/- were not statistically different from WT littermates. Representative images are shown. The scale bar is 100um. The respective Ki67 (B), Myc (D), Id1 (F), Sox9 (H) and Tunel (J) positive cells were counted (n = 25 tubules) in Id4+/+ and Id4-/- cross sections and subjected to t-test (** P < 0.01, *** P < 0.001, inset).