Fig. 1.

Overview of mammalian metanephric development. a The kidney is initiated via reciprocal induction events between the epithelial ureteric bud (UB), which arises from the mesonephric duct, and the metanephric mesenchyme (MM), which condenses to form a cap mesenchyme (CM). b Around the advancing ureteric tips (UT), the CM is induced to form a pre-tubular aggregate (PA) which then undergoes a mesenchyme-to-epithelial transition to form a renal vesicle (RV) surrounded by a basement membrane. The formation of each RV represents the initiation of a single nephron. c The RV proliferates and elongates to form first a comma-shaped body (CB) and then an S-shaped body (SB). Vascular endothelial cells are drawn into the cleft at the proximal end of this structure to form the glomerular capillaries. The other end of the forming nephron fuses with the UT at the late RV stage [73]. d A single nephron in the mammalian kidney. e Continued patterning of the elongating uriniferous tubule results in segmentation into the various functional regions of the nephron, including the proximal tubule and the distal tubule with an intervening loop of Henle (LH). The recruitment of vasculature and mesangial cells into the proximal end of this tubule forms the renal corpuscle (RC). PCT Proximal convoluted tubule, PST proximal straight tubule, S1–3 segment 1–3, DCT distal convoluted tubule, DST distal straight tubule, CT connecting tubule, CCD cortical collecting duct, MCD medullary collecting duct