TY - JOUR
T1 - Stage-sensitive blockade of pituitary somatomammotrope development by targeted expression of a dominant negative epidermal growth factor receptor in transgenic mice
AU - Roh, Meejeon
AU - Paterson, Andrew J.
AU - Asa, Sylvia L.
AU - Chin, Edward
AU - Kudlow, Jeffrey E.
PY - 2001
Y1 - 2001
N2 - The epidermal growth factor receptor (EGFR) and its ligands EGF and transforming growth factor-α (TGFα) are expressed in the anterior pituitary, and overexpression of TGFα in the lactotrope cells of the pituitary gland in transgenic mice results in lactotrope hyperplasia and adenomata, suggesting a role for EGFR signaling in pituitary cell proliferation. To address the role of EGFR signaling in pituitary development in vivo, we blocked EGFR signaling in transgenic mice using the dominant negative properties of a mutant EGFR lacking an intracellular protein kinase domain (EGFR-tr). We directed EGFR-tr expression to GH- and PRLproducing cells using GH and PRL promoters, and a tetracycline-inducible gene expression system, to allow temporal control of gene expression. EGFR-tr overexpression in GH-producing cells during embryogenesis resulted in dwarf mice with pituitary hypoplasia. Both somatotrope and lactotrope development were blocked. However, when EGFR-tr overexpression was delayed to the postnatal period either by directing its expression with the PRL promoter or by delaying the onset of induction with tetracycline in the GH cells, no specific phenotype was observed. Lactotrope hyperplasia during pregnancy also occurred normally in the PRL-EGFR-tr mice. These data suggest that EGFR signaling is required for the differentiation and/or maintenance of somatomammotropes early in pituitary organogenesis but not later in life.
AB - The epidermal growth factor receptor (EGFR) and its ligands EGF and transforming growth factor-α (TGFα) are expressed in the anterior pituitary, and overexpression of TGFα in the lactotrope cells of the pituitary gland in transgenic mice results in lactotrope hyperplasia and adenomata, suggesting a role for EGFR signaling in pituitary cell proliferation. To address the role of EGFR signaling in pituitary development in vivo, we blocked EGFR signaling in transgenic mice using the dominant negative properties of a mutant EGFR lacking an intracellular protein kinase domain (EGFR-tr). We directed EGFR-tr expression to GH- and PRLproducing cells using GH and PRL promoters, and a tetracycline-inducible gene expression system, to allow temporal control of gene expression. EGFR-tr overexpression in GH-producing cells during embryogenesis resulted in dwarf mice with pituitary hypoplasia. Both somatotrope and lactotrope development were blocked. However, when EGFR-tr overexpression was delayed to the postnatal period either by directing its expression with the PRL promoter or by delaying the onset of induction with tetracycline in the GH cells, no specific phenotype was observed. Lactotrope hyperplasia during pregnancy also occurred normally in the PRL-EGFR-tr mice. These data suggest that EGFR signaling is required for the differentiation and/or maintenance of somatomammotropes early in pituitary organogenesis but not later in life.
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U2 - 10.1210/mend.15.4.0625
DO - 10.1210/mend.15.4.0625
M3 - Article
C2 - 11266511
AN - SCOPUS:0035054851
SN - 0888-8809
VL - 15
SP - 600
EP - 613
JO - Molecular Endocrinology
JF - Molecular Endocrinology
IS - 4
ER -