During animal development, complex signals determine and organize a vast number of tissues using a very small number of signal transduction pathways. These developmental signaling pathways determine cell fates through a coordinated transcriptional response that remains poorly understood. The Wnt pathway is involved in a variety of these cellular functions, and its signals are transmitted in part through a β-catenin/TCF transcriptional complex. Here we report an in vivo Drosophila assay that can be used to distinguish between activation, de-repression and repression of transcriptional responses, separating upstream and downstream pathway activation and canonical/non-canonical Wnt signals in embryos. We find specific sets of genes downstream of both β-catenin and TCF with an additional group of genes regulated by Wnt, while the non-canonical Wnt4 regulates a separate cohort of genes. We correlate transcriptional changes with phenotypic outcomes of cell differentiation and embryo size, showing our model can be used to characterize developmental signaling compartmentalization in vivo.
Molecular analysis of the armadillo locus: uniformly distributed transcripts and a protein with novel internal repeats are associated with a Drosophila segment polarity gene
pangolin encodes a Lef-1 homologue that acts downstream of Armadillo to transduce the Wingless signal in Drosophila
Armadillo coactivates transcription driven by the product of the Drosophila segment polarity gene dTCF
Antagonist activity of DWnt-4 and wingless in the Drosophila embryonic ventral ectoderm and in heterologous Xenopus assays
Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method
Wg/Wnt signal can be transmitted through arrow/LRP5,6 and Axin independently of Zw3/Gsk3beta activity
Beta-catenin directly displaces Groucho/TLE repressors from Tcf/Lef in Wnt-mediated transcription activation
Planar polarization of the denticle field in the Drosophila embryo: roles for Myosin II (zipper) and fringe
Wnt, Hedgehog and junctional Armadillo/beta-catenin establish planar polarity in the Drosophila embryo
Actomyosin contractility and Discs large contribute to junctional conversion in guiding cell alignment within the Drosophila embryonic epithelium
Cell type-specific binding patterns reveal that TCF7L2 can be tethered to the genome by association with GATA3
Distinct DNA binding sites contribute to the TCF transcriptional switch in C. elegans and Drosophila
Bipartite recognition of DNA by TCF/Pangolin is remarkably flexible and contributes to transcriptional responsiveness and tissue specificity of wingless signaling
Stem cell signaling. An integral program for tissue renewal and regeneration: Wnt signaling and stem cell control
JASPAR 2016: a major expansion and update of the open-access database of transcription factor binding profiles
Tissue- and stage-specific Wnt target gene expression is controlled subsequent to β-catenin recruitment to cis-regulatory modules
Coupling optogenetics and light-sheet microscopy, a method to study Wnt signaling during embryogenesis
Cadherins and Catenins
Cadherins (named for "calcium-dependent adhesion") are a type of cell adhesion molecule (CAM) that is important in the formation of adherens junctions to bind cells with each other. Catenins are a family of proteins found in complexes with cadherin cell adhesion molecules of animal cells: alpha-catenin can bind to β-catenin and can also bind actin. β-catenin binds the cytoplasmic domain of some cadherins. Discover the latest research on cadherins and catenins here.
An adherens junction is defined as a cell junction whose cytoplasmic face is linked to the actin cytoskeleton. They can appear as bands encircling the cell (zonula adherens) or as spots of attachment to the extracellular matrix (adhesion plaques). Adherens junctions uniquely disassemble in uterine epithelial cells to allow the blastocyst to penetrate between epithelial cells. Discover the latest research on adherens junctions here.