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Transcriptional response induced by Wnt signaling in Caenorhabditis elegans affects lateral and ventral hypodermal cell development

ABSTRACT: The evolutionarily conserved Wnt/?-catenin signaling pathway plays a fundamental role during metazoan development, regulating numerous processes including cell fate specification, cell migration, and stem cell renewal. Wnt ligand binding leads to stabilization of the transcriptional effector ?-catenin and upregulation of target gene expression to mediate a cellular response. During larval development of the nematode Caenorhabditis elegans, Wnt/?-catenin pathways act in fate specification of two hypodermal cell types, the ventral vulval precursor cells (VPCs) and the lateral seam cells. Because little is known about targets of the Wnt signaling pathways acting during larval VPC and seam cell differentiation, we sought to identify genes regulated by Wnt signaling in these two hypodermal cell types. We conditionally activated Wnt signaling in larval animals and performed cell type?specific "mRNA tagging" to enrich for VPC and seam cell?specific mRNAs, and then used microarray analysis to examine gene expression compared to control animals. Two hundred thirty-nine genes activated in response to Wnt signaling were identified, and we characterized 50 genes further. The majority of these genes are expressed in seam and/or vulval lineages during normal development, and reduction of function for nine genes caused defects in the proper division, fate specification, fate execution, or differentiation of seam cells and vulval cells. Therefore, the combination of these techniques was successful at identifying potential cell type?specific Wnt pathway target genes from a small number of cells and at increasing our knowledge of the specification and behavior of these C. elegans larval hypodermal cells.

ORGANISM(S): Caenorhabditis elegans

PROVIDER: GSE52747 | GEO | 2015/11/18

SECONDARY ACCESSION(S): PRJNA229965

REPOSITORIES: GEO

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Project description:The Wnt signaling pathway plays a fundamental role during the development of metazoans, where it functions in the regulation of diverse processes including cell fate specification, cell migration, and stem cell renewal. Activation of the beta-catenin dependent or canonical Wnt signaling pathway upregulates expression of Wnt target genes to mediate an appropriate cellular response. In the nematode C. elegans, a Wnt signaling pathway similar to the canonical pathway regulates several processes during larval development, however few target genes of this pathway have been identified. To address this deficit, we conditionally activated Wnt signaling in living animals during a defined stage of larval life by expressing a dominant, activated beta-catenin protein, then used microarray analysis to identify genes showing altered expression compared to control animals. In this way we identified 166 differentially expressed genes, of which 104 were upregulated. A subset of the upregulated genes were validated by qPCR and showed altered expression in Wnt pathway mutants with decreased or increased Wnt signaling; we consider these genes to be candidate Wnt pathway targets in the C. elegans hermaphrodite larva. Amongst these was a group of 6 genes, including the cuticular collagen genes, bli-1 col-38, col-49 and col-71, that show a peak of expression in the mid L4 stage during normal development. The L4 expression of these genes suggests they may be expressed for use in the adult cuticle, and consistent with this, reduction of function for several of the genes leads to phenotypes suggestive of defects in cuticle function or integrity. Therefore this work has identified a large number of putative Wnt pathway target genes during larval life, including a small subset of Wnt-regulated collagen genes that may function in synthesis of the adult cuticle. a single pulse heat shock, inducing over-activated signal transduction in the Exp. Three treatment with three control strains of the identical genetical background strains

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Transcriptional response induced by Wnt signaling in Caenorhabditis elegans affects lateral and ventral hypodermal cell development

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