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Mark Peifer - One of the best experts on this subject based on the ideXlab platform.
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2016Co-Authors: Mark Peifer, Cordelia Rauskolb, Michelle Williams, Bob RigglemanAbstract:The Segment Polarity Gene armadillo interacts with the wingless signalin
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armadillo coactivates transcription driven by the product of the drosophila Segment Polarity Gene dtcf
Cell, 1997Co-Authors: Marc Van De Wetering, Amy Bejsovec, Robert Cavallo, Dennis Dooijes, Joseph Loureiro, Arne Ypma, Deborah A Hursh, Tamara L Jones, Moniek Van Beest, Mark PeiferAbstract:Abstract The vertebrate transcription factors TCF (T cell factor) and LEF (lymphocyte enhancer binding factor) interact with β-catenin and are hypothesized to mediate Wingless/Wnt signaling. We have cloned a maternally expressed Drosophila TCF family member, dTCF. dTCF binds a canonical TCF DNA motif and interacts with the β-catenin homolog Armadillo. Previous studies have identified two regions in Armadillo required for Wingless signaling. One of these interacts with dTCF, while the other constitutes a transactivation domain. Mutations in dTCF and expression of a dominant-negative dTCF transGene cause a Segment Polarity phenotype and affect expression of the Wingless target Genes engrailed and Ultrabithorax . Epistasis analysis positions dTCF downstream of armadillo . The Armadillo–dTCF complex mediates Wingless signaling as a bipartite transcription factor.
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Cell adhesion and signal transduction: the Armadillo connection
Trends in cell biology, 1995Co-Authors: Mark PeiferAbstract:The products of the Drosophila Segment Polarity Gene armadillo and its vertebrate homologue beta-catenin are components of the signal transduction pathway for Wingless/Wnt-1; this signal regulates cell-fate choices in embryos of the fruit fly Drosophila and vertebrates. Armadillo/beta-catenin is also a component of cell-cell adherens junctions in epithelia. How can these two seemingly distinct roles be reconciled? Evidence suggests that Armadillo has distinct functions: one in the adherens junction and one or more in the cytoplasm. The biochemical role of Armadillo may be to serve as a scaffold upon which different multiprotein complexes are assembled.
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phosphorylation of the drosophila adherens junction protein armadillo roles for wingless signal and zeste white 3 kinase
Developmental Biology, 1994Co-Authors: Mark Peifer, Li Mei Pai, Michael CaseyAbstract:The Drosophila Segment Polarity Gene product Armadillo provides a link between two seemingly separate processes, regulation of Segmental pattern by the Wingless intercellular signal and the function of cell-cell adherens junctions. armadillo was originally identified because of its Segment Polarity phenotype but subsequently was found to be the homolog of the vertebrate adherens junction protein beta-catenin. We examined the nature of the post-translational modification of Armadillo and its possible role in regulating Armadillo function. Armadillo is a phosphoprotein. Its level of phosphorylation varies both during embryonic development and from tissue to tissue. Phosphorylation occurs on both serine or threonine and tyrosine residues. Finally, Wingless signal negatively regulates Armadillo phosphorylation, while the Segment Polarity Gene product Zeste-white 3, a serine/threonine protein kinase, promotes Armadillo phosphorylation. We discuss the implications of these results for regulation of Wingless/Wnt-1 signaling and adherens junction function.
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a role for the drosophila Segment Polarity Gene armadillo in cell adhesion and cytoskeletal integrity during ooGenesis
Development, 1993Co-Authors: Mark Peifer, Sandra Orsulic, Dari Sweeton, Eric WieschausAbstract:The epithelial sheet is a structural unit common to many tissues. Its organization appears to depend on the function of the multi-protein complexes that form adherens junctions. Elegant cell biological experiments have provided support for hypotheses explaining the function of adherens junctions and of their components. These systems, however, lack the ability to test function within an entire organism during development. The realization that the product of the Drosophila Segment Polarity Gene armadillo is related to the vertebrate adhesive junction components plakoglobin and beta-catenin led to the suggestion that armadillo might provide a Genetic handle to study adhesive junction structure and function. An examination of the potential function of Armadillo in cell-cell adhesive junctions was initiated using the Drosophila ovary as the model system. We examined the distribution of Armadillo in the Drosophila ovary and demonstrated that this localization often parallels the location of cell-cell adhesive junctions. The consequences of removing armadillo function from the germ-line cells of the ovary were also examined. Germ-line armadillo mutations appear to disrupt processes requiring cell adhesion and integrity of the actin cytoskeleton, consistent with a role for Armadillo in cell-cell adhesive junctions. We have also used armadillo mutations to examine the effects on ovarian development of altering the stereotyped cell arrangements of the ovary. The implications of these results for the role of adhesive junctions during development are discussed.
Eric Wieschaus - One of the best experts on this subject based on the ideXlab platform.
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The Vertebrate Adhesive Junction Proteins-catenin and Plakoglobin and the Drosophila Segment Polarity Gene armadillo Form a MultiGene Family with Similar Properties
2013Co-Authors: Mark Peffer, Eric Wieschaus, Pierre D. Mccrea, Kathleen J Green, Barry M. GumbinerrAbstract:Abstract. Three proteins identified by quite different criteria in three different systems, the Drosophila Segment Polarity Gene armadillo, the human desmosomal protein plakoglobin, and the Xenopus E-cadherinassociated protein ~-catenin, share amino acid sequence similarity. These findings raise questions about the relationship among the three molecules and their roles in different cell-ceil adhesive junctions. We have found that antibodies against the Drosophila Segment Polarity Gene armadillo cross react with a conserved vertebrate protein. This protein is membrane associated, probably via its interaction with a cadherinlike molecule. This cross-reacting protein is the cadherin-associated protein fl-catenin. Using anti-armadillo and antiplakoglobin antibodies, it wa
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Segment Polarity Gene interactions modulate epidermal patterning in Drosophila embryos
Development, 1993Co-Authors: Amy Bejsovec, Eric WieschausAbstract:Each Segment of a Drosophila larva shows a precisely organized pattern of cuticular structures, indicating diverse cellular identities in the underlying epidermis. Mutations in the Segment Polarity Genes alter the cuticle pattern secreted by the epidermal cells; these mutant patterns provide clues about the role that each Gene product plays in the development of wild-type epidermal pattern. We have analyzed embryos that are multiply mutant for five key patterning Genes: wingless, patched, engrailed, naked and hedgehog. Our results indicate that wild-type activity of these five Segment Polarity Genes can account for most of the ventral pattern elements and that their Gene products interact extensively to specify the diverse cellular identities within the epidermis. Two pattern elements can be correlated with individual Gene action: wingless is required for formation of naked cuticle and engrailed is required for formation of the first row of denticles in each abdominal denticle belt. The remaining cell types can be produced by different combinations of the five Gene activities. wingless activity Generates the diversity of cell types within the Segment, but each specific cell identity depends on the activity of patched, engrailed, naked and hedgehog. These molecules modulate the distribution and interpretation of wingless signalling activity in the ventral epidermal cells and, in addition, each can contribute to pattern through a pathway independent of the wingless signalling pathway.
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a role for the drosophila Segment Polarity Gene armadillo in cell adhesion and cytoskeletal integrity during ooGenesis
Development, 1993Co-Authors: Mark Peifer, Sandra Orsulic, Dari Sweeton, Eric WieschausAbstract:The epithelial sheet is a structural unit common to many tissues. Its organization appears to depend on the function of the multi-protein complexes that form adherens junctions. Elegant cell biological experiments have provided support for hypotheses explaining the function of adherens junctions and of their components. These systems, however, lack the ability to test function within an entire organism during development. The realization that the product of the Drosophila Segment Polarity Gene armadillo is related to the vertebrate adhesive junction components plakoglobin and beta-catenin led to the suggestion that armadillo might provide a Genetic handle to study adhesive junction structure and function. An examination of the potential function of Armadillo in cell-cell adhesive junctions was initiated using the Drosophila ovary as the model system. We examined the distribution of Armadillo in the Drosophila ovary and demonstrated that this localization often parallels the location of cell-cell adhesive junctions. The consequences of removing armadillo function from the germ-line cells of the ovary were also examined. Germ-line armadillo mutations appear to disrupt processes requiring cell adhesion and integrity of the actin cytoskeleton, consistent with a role for Armadillo in cell-cell adhesive junctions. We have also used armadillo mutations to examine the effects on ovarian development of altering the stereotyped cell arrangements of the ovary. The implications of these results for the role of adhesive junctions during development are discussed.
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The product of the Drosophila melanogaster Segment Polarity Gene armadillo is highly conserved in sequence and expression in the housefly Musca domestica
Journal of Molecular Evolution, 1993Co-Authors: Mark Peifer, Eric WieschausAbstract:Segmental pattern in Drosophila melanogaster is set up via a set of cell-cell interactions mediated by the products of the Segment Polarity Genes. Among these is the armadillo Gene, whose product seems to be required for the reception of an intercellular signal encoded by the wingless Gene. As part of our effort to relate the structure of the armadillo protein to its function within the cell, we have examined the evolutionary conservation of the armadillo Gene during insect evolution. We have cloned the armadillo Gene from the housefly, Musca domestica , which diverged from Drosophila 100 million years ago. The Musca protein is 97.5% identical to that in Drosophila , while the noncoding sequences have diverged extensively. This remarkable degree of conservation at the protein level is mirrored in the expression pattern of the armadillo protein. Antibodies against the Drosophila protein cross-react with a Musca protein of the appropriate size. We have also used these antibodies to show that the Musca armadillo protein has a pattern of expression in larval and adult tissues similar to that of Drosophila armadillo . We discuss the implications of conservation of structure and expression for the cellular role of the armadillo protein and its mammalian homologs.
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the vertebrate adhesive junction proteins beta catenin and plakoglobin and the drosophila Segment Polarity Gene armadillo form a multiGene family with similar properties
Journal of Cell Biology, 1992Co-Authors: Mark Peifer, Eric Wieschaus, Pierre D. Mccrea, Kathleen J Green, Barry M GumbinerAbstract:Three proteins identified by quite different criteria in three different systems, the Drosophila Segment Polarity Gene armadillo, the human desmosomal protein plakoglobin, and the Xenopus E-cadherin-associated protein beta-catenin, share amino acid sequence similarity. These findings raise questions about the relationship among the three molecules and their roles in different cell-cell adhesive junctions. We have found that antibodies against the Drosophila Segment Polarity Gene armadillo cross react with a conserved vertebrate protein. This protein is membrane associated, probably via its interaction with a cadherin-like molecule. This cross-reacting protein is the cadherin-associated protein beta-catenin. Using anti-armadillo and antiplakoglobin antibodies, it was shown that beta-catenin and plakoglobin are distinct molecules, which can coexist in the same cell type. Plakoglobin interacts with the desmosomal glycoprotein desmoglein I, and weakly with E-cadherin. Although beta-catenin interacts tightly with E-cadherin, it does not seem to be associated with either desmoglein I or with isolated desmosomes. Anti-armadillo antibodies have been further used to determine the intracellular localization of beta-catenin, and to examine its tissue distribution. The implications of these results for the structure and function of different cell-cell adhesive junctions are discussed.
Norbert Perrimon - One of the best experts on this subject based on the ideXlab platform.
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the Segment Polarity Gene porcupine encodes a putative multitransmembrane protein involved in wingless processing
Genes & Development, 1996Co-Authors: Tatsuhiko Kadowaki, John Klingensmith, Elizabeth L Wilder, Kimon C Zachary, Norbert PerrimonAbstract:The Wnt protein Wingless (Wg) functions as a signal in patterning of both the Drosophila embryo and imaginal discs. Lack of porcupine (porc) activity is associated with mutant phenotypes similar to those of wg mutations. In porc mutant embryos, Wg protein is confined to the cells that produce it, suggesting that Porc plays a role in processing or secretion of Wg. porc encodes a novel transmembrane protein that appears to be concentrated at the endoplasmic reticulum. We present both Genetic and in vitro evidence demonstrating that porc is involved specifically in the processing of Wg. We identified a human sequence related to Porc suggesting the existence of a family of proteins involved in processing of Wnts.
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isolation and characterization of a mouse homolog of the drosophila Segment Polarity Gene dishevelled
Developmental Biology, 1994Co-Authors: Daniel J Sussman, Roel Nusse, John Klingensmith, Patricia C Salinas, Pamela S Adams, Norbert PerrimonAbstract:Abstract In the Drosophila embryo dishevelled (dsh) function is required by target cells in order to respond to wingless (wg, the homolog of Wnt-1), demonstrating a role for dsh in Wnt signal transduction. We have isolated a mouse homolog of the Drosophila dsh Segment Polarity Gene. The 695-amino-acid protein encoded by the mouse dishevelled Gene (Dvl-1) shares 50% identity (65% similarity) with dsh. Similarity searches of protein and DNA data bases revealed that Dvl-1 encodes an otherwise novel polypeptide. While no functional motifs were identified, one region of Dvl-1 was found to be similar to a domain of discs large-1 (dlg), a Drosophila tumor suppressor Gene. In the embryo, Dvl-1 is expressed in most tissues, with uniformly high levels in the central nervous system. From 7.5 days postcoitum Dvl-1 is expressed throughout the developing brain and spinal cord, including those regions expressing Wnt-1 and En. Expression of Dvl-1 in adult mice was found to be widespread, with brain and testis exhibiting the highest levels. The majority of Dvl-1 expression in the adult cerebellum is in the granular cell layer, similar to the pattern seen for engrailed-2 (En-2) . Throughout postnatal development of the brain Dvl-1 is highly expressed in areas of high neuronal cell density.
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dishevelled and armadillo act in the wingless signalling pathway in drosophila
Nature, 1994Co-Authors: Jasprien Noordermeer, Norbert Perrimon, John Klingensmith, Roel NusseAbstract:THE Wnt Genes encode conserved secreted proteins that play a role in normal development and tumoriGenesis1,2. Little is known about the signal transduction pathways of Wnt Gene products. One of the best characterized Wnt family members is the Drosophila Segment Polarity Gene wingless3–6. We have investigated whether Segment Polarity Genes with a wingless-like phenotype mediate the wingless signal. We used a wingless transGene controlled by a heat-shock promoter for Genetic epistasis experiments. We show that wingless acts through dishevelled and armadillo to affect the expression of the homeobox Gene engrailed and cuticle differentiation.
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the drosophila Segment Polarity Gene dishevelled encodes a novel protein required for response to the wingless signal
Genes & Development, 1994Co-Authors: John Klingensmith, Roel Nusse, Norbert PerrimonAbstract:: The Drosophila Wnt-1 homolog, wingless (wg), is involved in the signaling of patterning information in several contexts. In the embryonic epidermis, Wg protein is secreted and taken up by neighboring cells, in which it is required for maintenance of engrailed transcription and accumulation of Armadillo protein. The dishevelled (dsh) Gene mediates these signaling events as well as wg-dependent induction across tissue layers in the embryonic midgut. dsh is also required for the development processes in which wg functions in adult development. Overall, cells lacking dsh are unable to adopt fates specified by Wg. dsh functions cell autonomously, indicating that it is involved in the response of target cells to the Wg signal. dsh is expressed uniformly in the embryo and encodes a novel protein with no known catalytic motifs, although it shares a domain of homology with several junction-associated proteins. Our results demonstrate that dsh encodes a specific component of Wg signaling and illustrate that Wnt proteins may utilize a novel mechanism of extracellular signal transduction.
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mutations in the Segment Polarity Genes wingless and porcupine impair secretion of the wingless protein
The EMBO Journal, 1993Co-Authors: M Van Den Heuvel, Norbert Perrimon, John Klingensmith, C Harrymansamos, Roel NusseAbstract:Abstract We have characterized the molecular nature of mutations in wingless (wg), a Segment Polarity Gene acting during various stages of Drosophila development. Embryo-lethal alleles have undergone mutations in the protein-encoding domain of the Gene, including deletions and point mutations of conserved residues. In a temperature sensitive mutation, a conserved cysteine residue is replaced by a serine. In embryo-viable alleles, the wg transcriptional unit is not affected. Immunostaining of mutant embryos shows that the embryo-lethal alleles produce either no wg antigen or a form of the protein that is retained within cells. Interestingly, embryos mutant for the Segment Polarity Gene porcupine show a similar retention of the wg antigen. We have also transfected wild type wg alleles into Drosophila tissue culture cells, which then display wg protein on the cell surface and in the extracellular matrix. In similar experiments with mutant alleles, the proteins are retained in intracellular compartments and appear not to be secreted. These data provide further evidence that wg acts as a secreted factor and suggest that porcupine provides an accessory function for wg protein secretion or transport.
Roel Nusse - One of the best experts on this subject based on the ideXlab platform.
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the dishevelled protein is modified by wingless signaling in drosophila
Genes & Development, 1995Co-Authors: Shin-ichi Yanagawa, F E Van Leeuwen, Andreas Wodarz, John Klingensmith, Roel NusseAbstract:: Wingless (Wg) is an important signaling molecule in the development of Drosophila, but little is known about its signal transduction pathway. Genetic evidence indicates that another Segment Polarity Gene, dishevelled (dsh) is required for Wg signaling. We have recently developed a cell culture system for Wg protein activity, and using this in vitro system as well as intact Drosophila embryos, we have analyzed biochemical changes in the Dsh protein as a consequence of Wg signaling. We find that Dsh is a phosphoprotein, normally present in the cytoplasm. Wg signaling Generates a hyperphosphorylated form of Dsh, which is associated with a membrane fraction. Overexpressed Dsh becomes hyperphosphorylated in the absence of extracellular Wg and increases levels of the Armadillo protein, thereby mimicking the Wg signal. A deletional analysis of Dsh identifies several conserved domains essential for activity, among which is a so-called GLGF/DHR motif. We conclude that dsh, a highly conserved Gene, is not merely a permissive factor in Wg signaling but encodes a novel signal transduction molecule, which may function between the Wg receptor and more downstream signaling molecules.
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isolation and characterization of a mouse homolog of the drosophila Segment Polarity Gene dishevelled
Developmental Biology, 1994Co-Authors: Daniel J Sussman, Roel Nusse, John Klingensmith, Patricia C Salinas, Pamela S Adams, Norbert PerrimonAbstract:Abstract In the Drosophila embryo dishevelled (dsh) function is required by target cells in order to respond to wingless (wg, the homolog of Wnt-1), demonstrating a role for dsh in Wnt signal transduction. We have isolated a mouse homolog of the Drosophila dsh Segment Polarity Gene. The 695-amino-acid protein encoded by the mouse dishevelled Gene (Dvl-1) shares 50% identity (65% similarity) with dsh. Similarity searches of protein and DNA data bases revealed that Dvl-1 encodes an otherwise novel polypeptide. While no functional motifs were identified, one region of Dvl-1 was found to be similar to a domain of discs large-1 (dlg), a Drosophila tumor suppressor Gene. In the embryo, Dvl-1 is expressed in most tissues, with uniformly high levels in the central nervous system. From 7.5 days postcoitum Dvl-1 is expressed throughout the developing brain and spinal cord, including those regions expressing Wnt-1 and En. Expression of Dvl-1 in adult mice was found to be widespread, with brain and testis exhibiting the highest levels. The majority of Dvl-1 expression in the adult cerebellum is in the granular cell layer, similar to the pattern seen for engrailed-2 (En-2) . Throughout postnatal development of the brain Dvl-1 is highly expressed in areas of high neuronal cell density.
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dishevelled and armadillo act in the wingless signalling pathway in drosophila
Nature, 1994Co-Authors: Jasprien Noordermeer, Norbert Perrimon, John Klingensmith, Roel NusseAbstract:THE Wnt Genes encode conserved secreted proteins that play a role in normal development and tumoriGenesis1,2. Little is known about the signal transduction pathways of Wnt Gene products. One of the best characterized Wnt family members is the Drosophila Segment Polarity Gene wingless3–6. We have investigated whether Segment Polarity Genes with a wingless-like phenotype mediate the wingless signal. We used a wingless transGene controlled by a heat-shock promoter for Genetic epistasis experiments. We show that wingless acts through dishevelled and armadillo to affect the expression of the homeobox Gene engrailed and cuticle differentiation.
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the drosophila Segment Polarity Gene dishevelled encodes a novel protein required for response to the wingless signal
Genes & Development, 1994Co-Authors: John Klingensmith, Roel Nusse, Norbert PerrimonAbstract:: The Drosophila Wnt-1 homolog, wingless (wg), is involved in the signaling of patterning information in several contexts. In the embryonic epidermis, Wg protein is secreted and taken up by neighboring cells, in which it is required for maintenance of engrailed transcription and accumulation of Armadillo protein. The dishevelled (dsh) Gene mediates these signaling events as well as wg-dependent induction across tissue layers in the embryonic midgut. dsh is also required for the development processes in which wg functions in adult development. Overall, cells lacking dsh are unable to adopt fates specified by Wg. dsh functions cell autonomously, indicating that it is involved in the response of target cells to the Wg signal. dsh is expressed uniformly in the embryo and encodes a novel protein with no known catalytic motifs, although it shares a domain of homology with several junction-associated proteins. Our results demonstrate that dsh encodes a specific component of Wg signaling and illustrate that Wnt proteins may utilize a novel mechanism of extracellular signal transduction.
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mutations in the Segment Polarity Genes wingless and porcupine impair secretion of the wingless protein
The EMBO Journal, 1993Co-Authors: M Van Den Heuvel, Norbert Perrimon, John Klingensmith, C Harrymansamos, Roel NusseAbstract:Abstract We have characterized the molecular nature of mutations in wingless (wg), a Segment Polarity Gene acting during various stages of Drosophila development. Embryo-lethal alleles have undergone mutations in the protein-encoding domain of the Gene, including deletions and point mutations of conserved residues. In a temperature sensitive mutation, a conserved cysteine residue is replaced by a serine. In embryo-viable alleles, the wg transcriptional unit is not affected. Immunostaining of mutant embryos shows that the embryo-lethal alleles produce either no wg antigen or a form of the protein that is retained within cells. Interestingly, embryos mutant for the Segment Polarity Gene porcupine show a similar retention of the wg antigen. We have also transfected wild type wg alleles into Drosophila tissue culture cells, which then display wg protein on the cell surface and in the extracellular matrix. In similar experiments with mutant alleles, the proteins are retained in intracellular compartments and appear not to be secreted. These data provide further evidence that wg acts as a secreted factor and suggest that porcupine provides an accessory function for wg protein secretion or transport.
Moniek Van Beest - One of the best experts on this subject based on the ideXlab platform.
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drosophila rps3a a novel minute Gene situated between the Segment Polarity Genes cubitus interruptus and dtcf
Nucleic Acids Research, 1998Co-Authors: Moniek Van Beest, Hans Clevers, Mark A MortinAbstract:Genetic analysis of the small chromosome 4 of Drosophila has been hampered by the virtual lack of recombination. The Segment Polarity Gene cubitus interruptus (ci) maps to the most intensively studied locus on this chromosome. Up to four complementation groups have been found to be associated with ci. We and others have recently characterized a second Segment Polarity Gene, dTCF or pan, 12 kb upstream of ci, in a head-to-head configuration. During the course of these studies we identified a transcription unit in the intergenic region. We report here the cloning of cDNAs from this transcription unit, which encode the Drosophila homologue of the human ribosomal protein S3a (RpS3a). The RpS3a Gene is expressed ubiquitously and throughout development. A Minute allele, M(4)101, linked tightly to ci, was found to harbour an integration of a Doc retroposon in the promotor region of RpS3a. Thus, like other Minute loci, M(4)101 encodes a component of the protein synthesis machinery. These data further unravel the complex Genetics surrounding the ci and dTCF loci.
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genomic organization of the Segment Polarity Gene pan in drosophila melanogaster
Molecular Genetics and Genomics, 1998Co-Authors: Dennis Dooijes, Marc Van De Wetering, Moniek Van Beest, Tamara L Jones, G Boulanger, Hans Clevers, Mark A MortinAbstract:We previously described the molecular cloning of a mammalian T cell factor 1 (TCF-1)-like protein from Drosophila melanogaster, encoded by the pangolin (pan) locus, and demonstrated that it consists of a DNA binding domain similar to that of other high mobility group proteins and a protein-protein interaction domain that binds beta-catenin (Armadillo in Drosophila) but that it lacks a transcriptional activation domain. Here we show that the pan locus spans approximately 50 kb and the mRNA results from the splicing of 13 exons. We note remarkable conservation of the exon/intron boundaries between the human and D. melanogaster Genes, suggesting that they share a common ancestor. Chromosomal in situ hybridization locates pan to the base of chromosome 4, near the cubitus interruptus locus. Restriction map and sequence analyses confirm their close proximity. The small fourth chromosome undergoes little or no recombination and was previously reported to lack DNA polymorphisms; however, we note two DNA polymorphisms occurring in three combinations within the pan locus, demonstrating the presence of synonymous substitutions and the past occurrence of recombination. We present evidence suggesting that the protein encoded by pan is more similar to mammalian TCF-1 and Caenorhabditis elegans POP-1 than to mammalian LEF-1.
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armadillo coactivates transcription driven by the product of the drosophila Segment Polarity Gene dtcf
Cell, 1997Co-Authors: Marc Van De Wetering, Robert Cavallo, Dennis Dooijes, Moniek Van Beest, Johan H Van Es, Joseph Loureiro, Arne Ypma, Deborah A Hursh, Tamara L Jones, Amy BejsovecAbstract:The vertebrate transcription factors TCF (T cell factor) and LEF (lymphocyte enhancer binding factor) interact with beta-catenin and are hypothesized to mediate Wingless/Wnt signaling. We have cloned a maternally expressed Drosophila TCF family member, dTCF. dTCF binds a canonical TCF DNA motif and interacts with the beta-catenin homolog Armadillo. Previous studies have identified two regions in Armadillo required for Wingless signaling. One of these interacts with dTCF, while the other constitutes a transactivation domain. Mutations in dTCF and expression of a dominant-negative dTCF transGene cause a Segment Polarity phenotype and affect expression of the Wingless target Genes engrailed and Ultrabithorax. Epistasis analysis positions dTCF downstream of armadillo. The Armadillo-dTCF complex mediates Wingless signaling as a bipartite transcription factor.