1: Development. 2002 Jan;129(2):329-37. 

Pitx2 is required at multiple stages of pituitary organogenesis: pituitary
primordium formation and cell specification.

Suh H, Gage PJ, Drouin J, Camper SA.

Neuroscience Program, Department of Human Genetics, University of Michigan, Ann
Arbor, MI 48109-0638, USA.

Analysis of an allelic series in mice revealed that the Pitx2 homeobox gene is
required at multiple stages of pituitary development. It is necessary for
initiating expansion of Rathke's pouch and maintaining expression of the
fetal-specific transcription factors Hesx1 and Prop1. At later stages Pitx2 is
necessary for specification and expansion of the gonadotropes and Pit1 lineage
within the ventral and caudomedial anterior pituitary. Mechanistically, this is
due to the dependence of several critical lineage-specific transcription
factors, Pit1, Gata2, Egr1 and Sf1, on a threshold level of PITX2. The related
Pitx1 gene has a role in hormone gene transcription, and it is important late in
ontogeny for the final expansion of the differentiated cell types. Pitx1 and
Pitx2 have overlapping functions in the expansion of Rathke's pouch, revealing
the sensitivity of pituitary organogenesis to the dosage of the PITX family. The
model developed for PITX gene function in pituitary development provides a
better understanding of the etiology of Rieger syndrome and may extend to other
PITX-sensitive developmental processes.

PMID: 11807026 [PubMed - indexed for MEDLINE]


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