Abstract
Aardvark (Aar) is a Dictyostelium beta-catenin homologue with both cytoskeletal and signal transduction roles during development. Here, we show that loss of aar causes a novel phenotype where multiple stalks appear during late development. Ectopic stalks are preceded by misexpression of the stalk marker ST-lacZ in the surrounding tissue. This process does not involve the kinase GSK-3. Mixing experiments show that ectopic ST-lacZ expression and stalk formation are cell non-autonomous. The protein-cellulose matrix surrounding the stalk of aar mutant fruiting bodies is defective, and damage to the stalk of wild-type fruiting bodies leads to ectopic ST-lacZ expression. We postulate that poor synthesis of the stalk tube matrix allows diffusion of a stalk cell-inducing factor into the surrounding tissue.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Genetically Modified
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Cytoskeletal Proteins / deficiency
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Cytoskeletal Proteins / genetics*
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Cytoskeletal Proteins / physiology
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Dictyostelium / genetics*
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Dictyostelium / growth & development*
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Dictyostelium / physiology
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Extracellular Matrix Proteins / genetics
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Gene Expression Regulation, Developmental
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Genes, Protozoan
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Glycogen Synthase Kinase 3 / genetics
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Glycogen Synthase Kinase 3 / metabolism
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Glycogen Synthase Kinases / genetics
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Lac Operon
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Mutation
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Phenotype
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Protozoan Proteins / genetics
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Signal Transduction
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Trans-Activators / deficiency
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Trans-Activators / genetics*
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Trans-Activators / physiology
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beta Catenin
Substances
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Cytoskeletal Proteins
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Extracellular Matrix Proteins
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Protozoan Proteins
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Trans-Activators
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beta Catenin
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ecmB protein, Dictyostelium
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Glycogen Synthase Kinases
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Glycogen Synthase Kinase 3