The mammalian metanephros develops through reciprocal induction of
ureteric bud cells and the intermediate (metanephric) mesenchyme. The latter form most of the
nephron - the filtration unit and most of the tubules, while ureteric bud cells preferentially
contribute to the collection system.
The early events of nephrogenesis, where mesenchymal cells are
transformed into epithelial and glomerular precursors is only partly understood. We have used in vitro organ culture in the past to identify a number of genes
that are regulated during the initial steps of metanephric induction and
development. Examples are the
genes. All four genes encode members of larger protein families and we have
characterized gene expression patterns for the entire families in each case.
The kidney organ culture system is depicted below. This allows
part of the embryonic kidney development to be monitored and experimentally
altered during the course of up to 10 days. When kidney rudiments from
HoxB7-EGFP mice are used the ureter can be visualized by UV illumination (ref;