Noggin regulates Bmp4 activity during pituitary induction.
Bone morphogenetic protein (Bmp) signaling is critical for the development and patterning of the mouse pituitary from the initial induction of Rathke's pouch to cell specification in the anterior lobe. We examined the regulation of Bmp signaling during pituitary development by analyzing null embryos for noggin, a Bmp 2 and 4 antagonist. Noggin is expressed in the ventral diencephalon during Rathke's pouch induction, in the underlying cartilage plate during cell specification and in the adult anterior pituitary gland. Noggin null embryos have a variable pituitary phenotype, which ranges from a rostrally displaced Rathke's pouch to induction of secondary pituitary tissue. While cell specification in the anterior pituitary appears normal, patterning in the ventral diencephalon is disrupted; Bmp4 activity is expanded resulting in Fibroblast growth factor 10 repression and in a rostral shift in the boundary between the Bmp4 and Sonic hedgehog expression domains. The expanded domain of Bmp4 activity also results in additional invaginations of oral ectoderm and can shift the position of Rathke's pouch or create secondary pituitary tissue. This work demonstrates the importance of attenuating the activity of Bmp signaling during pituitary induction in order to maintain the proper balance of signaling factors necessary for pituitary organogenesis.
Davis
Shannon W
SW
Department of Human Genetics, University of Michigan Medical School, 4909 Buhl Building, 1241 E. Catherine St., Ann Arbor, MI 48109-0618, USA.
Camper
Sally A
SA
D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D004627:Embryonic Induction / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D010902:Pituitary Gland / Q000196:embryology* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D000099176:Noggin Protein
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D000099176:Noggin Protein; C525810:Bmp4 protein, mouse