What Can a Frog Tell Us about Human Kidney Development

The development of the first form of kidney, the pronephros, in the frog Xenopus is most attractive to study nephrogenesis in vertebrates. The formation of the pronephros can be readily analyzed during organogenesis by manipulating the activity of specific factors in the developing Xenopus embryo. In addition embryonic explants of Xenopus can be induced to pronephric differentiation in vitro by adding defined signaling molecules. The available data show that the same transcription factors and signaling molecules play a role in Xenopus pronephros differentiation as in mammalian nephrogenesis. This allows the dissection of the molecular and cellular events relevant for nephrogenesis in an easy amenable experimental system. Thus, Xenopus pronephros formation can be used to define nephrogenic regulators and to identify the morphogenetic potential of mutated factors associated with renal diseases in humans.