The structure of a mammalian kidney is parsed into large collections of polarized nephrons,
and each segment is home to a diverse community of cells that specialize in renal endocrine
and excretory functions. Early developmental lengthening and diversification of nephron
segments along a proximal-–distal axis initiate all subsequent facets of tubular growth and
function. Morphogenic cues and biochemical interactions that are critical to this process are
starting to emerge. The underlying principles of regional cell signaling and transcriptional …