Deletion of the prorenin receptor in the ureteric bud in mice inhibits Dot1/H3K79 pathway

Background: The prorenin receptor (PRR) plays a critical role in ureteric bud (UB) branching morphogenesis. DOT1 Like (DOT1L), a histone methyltransferase specific for Histone 3 lysine 79 (H3K79), is important for differentiation of the UB-derived renal collecting duct cells. In this study, we tested whether DOT1L/H3 dimethyl K79 (H3m2K79) are regulated by PRR deletion in the UB and UB-derived collecting ducts in the embryonic mouse kidneys. Methods: Mutant Hoxb7(Cre+)/PRRflox/flox (PRRUB-/-) and control PRRUB+/+, mice were studied on embryonic (E) day E17.5. DOT1L mRNA and protein expression in the kidney was examined by real-time qRT-PCR and immunohistochemistry, respectively. H3m2K79 protein expression was determined by immunohistochemistry and Western blot analysis. Results: DOT1L mRNA levels were decreased in mutant compared to control mice (0.68 +/- 0.06 vs. 1.0 +/- 0.01, p < 0.01). DOT1L and H3m2K79 immunostaining was reduced in the mutant vs. control kidneys (Dot1: 0.62 +/- 0.03 vs. 1.0 +/- 0.01, p < 0.05; H3m2K79: 0.64 +/- 0.04 vs.1.1 +/- 0.01. p < 0.05.). Western blot analysis revealed decreased H3m2K79 protein levels in mutant compared to control kidneys (1.0 +/- 0.06 vs. 1.5 +/- 0.02, p < 0.05). Conclusion: Targeted deletion of the PRR in the UB and UB-derived collecting ducts results in reduced DOT1L gene/protein and H3m2K79 protein expression in the embryonic mouse metanephroi in vivo.<br />