Wnt3a regulates Lef-1 expression during airway submucosal gland morphogenesis.
Regulation of the lymphoid enhancer factor 1 (Lef-1) transcription factor is important for the inductive formation of many epithelial-derived appendages including airway submucosal glands (SMGs). Although Wnts have been linked to developmental processes involving transcriptional activation of the Lef-1 protein, there is little in vivo information directly linking Wnts with the transcriptional regulation of the Lef-1 promoter. In the present study, we hypothesized that Wnt3a directly regulates Lef-1 gene expression required for SMG morphogenesis in mice. In support of this hypothesis, TOPGAL reporter mice demonstrated activation of beta-catenin/Tcf complexes during early phases of SMG development and immunolocalization studies confirmed abundant expression of Tcf4, but not Tcf1 or Tcf3, at this stage. ChIP analysis in primary airway epithelial cells revealed that Tcf4 associates with a known Wnt Responsive Region in the Lef-1 promoter and transfection of Cos-1 cells with dominant active beta-catenin and Tcf4 synergistically activated the Lef-1 promoter. Using Wnt3a deficient and Lef-1 promoter-GFP reporter mice, we also demonstrate that Wnt3a induces Lef-1 gene expression in newly forming SMG buds of mice and is required for the maintenance of gland bud growth. These findings provide the first in vivo evidence that Wnt3a can transcriptionally regulate the Lef-1 gene.
Driskell
Ryan R
RR
Department of Anatomy and Cell Biology, Iowa City, IA 52242, USA.
Goodheart
Michael
M
Neff
Traci
T
Liu
Xiaoming
X
Luo
Meihui
M
Moothart
Chris
C
Sigmund
Curt D
CD
Hosokawa
Ryoichi
R
Chai
Yang
Y
Engelhardt
John F
JF
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D015153:Blotting, Western; D047369:Chromatin Immunoprecipitation; D005088:Exocrine Glands / Q000196:embryology*; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009024:Morphogenesis / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D020545:Respiratory Mucosa / Q000196:embryology / Q000378:metabolism*; D051820:TCF Transcription Factors / Q000378:metabolism; D000073940:Transcription Factor 4; D051153:Wnt Proteins / Q000378:metabolism*; D060508:Wnt3 Protein; D060509:Wnt3A Protein
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C497574:Lef1 protein, mouse; D051821:Lymphoid Enhancer-Binding Factor 1; D009419:Nerve Tissue Proteins; D051820:TCF Transcription Factors; C090743:Tcf4 protein, mouse; D000073940:Transcription Factor 4; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse