MULTISTEP CONTROL OF PITUITARY ORGANOGENESIS

Lhx3 and Lhx4 (Gsh4), two closely related LIM homeobox genes, determin e formation of the pituitary gland in mice. Rathke's pouch is formed i n two steps-first as a rudiment and later as a definitive pouch. Lhx3 and Lhx4 have redundant control over formation of the definitive pouch . Lhx3 controls a subsequent step of pituitary fate commitment. Therea fter, Lhx3 and Lhx4 together regulate proliferation and differentiatio n of pituitary-specific cell lineages. Thus, Lhx3 and Lhx4 dictate pit uitary organ identity by controlling developmental decisions at multip le stages of organogenesis.