Project description:The morphogen Sonic H edgehog governs a wide range of developmental processes. The zebrafish genetic mutant iguana has vascular stability defects due to decreased Shh signaling. Using iguana mutant embryos and embryos treated with the Hedgehog pathway inhibitor cyclopamine, we conducted a microarray to determine genes that are specifically regulated by Shh signaling, and that might mediate vascular stability. We populate a list of 40 genes to have significantly altered expression in both conditions. Using in situ hybridization and quantitative real-time PCR, we verify the expression changes seen in a subset of genes from the list and determine their localization during embryonic development. We then assay the functional relevance of one of the array hits, the cell-cycle regulator pim1, which was upregulated on the microarray. By overexpressing pim1, we observe a loss of vascular stability, similar to that of iguana mutants. Furthermore, chemical inhibition of pim1 in iguana mutant embryos or cyclopamine treated embryos rescues vascular stability. We conclude that the microarray identified a set of genes that are differentially expressed in two distinct modes of Shh signaling interference. Furthermore, this set of genes contains a high proportion of factors potentially involved in vascular stabilization. The identification of these genes is the first step in defining the molecular mechanism by which Shh promotes vascular stability. 3 biological cyclopamine treated samples plus 3 biological DMSO treated controls, plus 3 biological replicates of iguana mutants plus 3 wild type sibling controls, all collected at 30 hpf
Project description:The morphogen Sonic H edgehog governs a wide range of developmental processes. The zebrafish genetic mutant iguana has vascular stability defects due to decreased Shh signaling. Using iguana mutant embryos and embryos treated with the Hedgehog pathway inhibitor cyclopamine, we conducted a microarray to determine genes that are specifically regulated by Shh signaling, and that might mediate vascular stability. We populate a list of 40 genes to have significantly altered expression in both conditions. Using in situ hybridization and quantitative real-time PCR, we verify the expression changes seen in a subset of genes from the list and determine their localization during embryonic development. We then assay the functional relevance of one of the array hits, the cell-cycle regulator pim1, which was upregulated on the microarray. By overexpressing pim1, we observe a loss of vascular stability, similar to that of iguana mutants. Furthermore, chemical inhibition of pim1 in iguana mutant embryos or cyclopamine treated embryos rescues vascular stability. We conclude that the microarray identified a set of genes that are differentially expressed in two distinct modes of Shh signaling interference. Furthermore, this set of genes contains a high proportion of factors potentially involved in vascular stabilization. The identification of these genes is the first step in defining the molecular mechanism by which Shh promotes vascular stability.