Analysis of WT1 gene expression during mouse nephrogenesis in organ culture.

The temporal and spatial expression patterns of the Wilms tumor gene, WT1, were studied during the organogenesis of the mouse kidney in vitro. In situ hybridization and immunocytochemistry localized cellular expression of WT1 in whole kidney organ cultures to the induced metanephric mesenchyme and developing podocytes. Organ cultures were further characterized immunocytochemically with antibodies that specifically labeled the different tubular epithelial components and supporting mesenchyme of the developing nephrons. In organ cultures, the WT1 expression pattern could be visualized in induced metanephric mesenchyme and entire cell cohorts of differentiating podocytes. Expression of WT1 and cell specific markers were retained in short-term monolayer cultures of dissociated kidneys. The development of the metanephric kidney in vitro involves a highly restricted temporal and spatial cellular expression pattern of WT1 which closely follows that observed in tissue sections from gestational kidney isolated during organogenesis in the mouse.