title: Identification of members of the Wnt signaling pathway in the embryonic pituitary gland.
abstract: Prop1 is one of several transcription factors important for the development of the pituitary gland. Downstream targets of PROP1 and other critical pituitary transcription factors remain largely unknown. We have generated a partial expression profile of the developing pituitary gland containing over 350 transcripts, using cDNA subtractive hybridization between Prop1(df/df) and wild-type embryonic pituitary gland primordia. Numerous classes of genes including transcription factors, membrane associated molecules, and cell cycle regulators were identified in this study. Of the transcripts, 34% do not have sequence similarity to known genes, but are similar to ESTs, and 4% represent novel sequences. Pituitary gland expression of a number of clones was verified using in situ hybridization. Several members of the Wnt signaling pathway were identified in the developing pituitary gland. The frizzled2 receptor, Apc, beta-catenin, groucho, and a novel isoform of TCF4 (officially named Tcf7l2) were identified in developing pituitary libraries. Three N-terminal alternatively spliced Tcf7l2 isoforms are reported here, each of which lacks a DNA-binding domain. Functional studies indicate that these isoforms can act as endogenous inhibitors of Wnt signaling in some contexts. This is the first report of Tcf7l2 and Fzd2 expression in the developing pituitary. These molecules may be important in mediating Wnt signaling during pituitary ontogeny. We expect other transcripts from these libraries to be involved in pituitary gland development.
authors.affiliation: Department of Human Genetics, University of Michigan Medical School, 4301 MSRBIII, 1500 W. Medical Center Dr., Ann Arbor, Michigan 48109-0638, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Douglas
authors.forename: M L
authors.initials: ML
authors.lastname: Brinkmeier
authors.forename: J A
authors.initials: JA
authors.lastname: Kennell
authors.forename: P
authors.initials: P
authors.lastname: Eswara
authors.forename: T A
authors.initials: TA
authors.lastname: Harrison
authors.forename: A I
authors.initials: AI
authors.lastname: Patrianakos
authors.forename: B S
authors.initials: BS
authors.lastname: Sprecher
authors.forename: M A
authors.initials: MA
authors.lastname: Potok
authors.forename: R H
authors.initials: RH
authors.lastname: Lyons
authors.forename: O A
authors.initials: OA
authors.lastname: MacDougald
authors.forename: S A
authors.initials: SA
authors.lastname: Camper
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D003598:Cytoskeletal Proteins / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D051157:Frizzled Receptors; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000196:embryology / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000235:genetics; D051820:TCF Transcription Factors; D015534:Trans-Activators; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors / Q000235:genetics*; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin
chemical_list: C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D051157:Frizzled Receptors; C489743:Fzd2 protein, mouse; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter; D051820:TCF Transcription Factors; C544894:TCF7L2 protein, human; C544895:Tcf7l2 protein, mouse; D015534:Trans-Activators; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; D004247:DNA