Klf6 Is a Zinc Finger Protein Expressed in a Cell-Specific Manner during Kidney Development

Molecular mechanisms that are responsible for the development of the renal collecting duct system during embryogenesis are still poorly understood. A mouse cDNA encoding a zinc finger protein, called Klf6, which is a member of the Krüppel-like family of transcription factors, has been cloned. Northern blot analyses showed that Klf6 was already expressed in 11.5-d postconception mouse embryos and that its expression persisted after birth. They also disclosed that Klf6 had a restricted pattern of expression. In situ hybridization experiments using mouse embryos showed that during kidney development, Klf6 was expressed selectively in the Wolffian duct and in its derivatives. During mesonephros development, it was expressed in the Wolffian duct but not in the mesonephric mesenchyme. Thereafter, Klf6 was expressed in the ureteric bud and its branches and in the collecting ducts, whereas it was not expressed in tubular structures that derive from the metanephric mesenchyme. Glomeruli were not labeled during early stages of differentiation, and it is only at the capillary stage that a staining of the mesangial area was observed, which persisted after birth. This pattern of expression is strikingly similar to the one of GATA-3, which is another zinc finger protein. It suggests that Klf6 may play a role during kidney development and in particular during the development of the renal collecting duct system, possibly in association with GATA-3.