The hedgehog signalling pathway is a conserved mechanism which acts in inductive processes in both vertebrate and invertebrate development to direct growth and patterning. In Drosophila, the secreted Hedgehog protein acts as a signal to induce non-autonomous activation in adjacent cells of either the decapentaplegic or wingless genes (both of which encode growth factor-like molecules), via inac...

Differentiation of the Drosophila compound eye from the eye imaginal disc is a progressive process: columns of cells successively differentiate in a posterior to anterior sequence, clusters of cells form at regularly spaced intervals within each column, and individual photoreceptors differentiate in a defined order within each cluster. The progression of differentiation across the eye disc is d...

During gastrulation in the mouse, mesoderm is induced and patterned by secreted signaling molecules, giving rise first to primitive erythroblasts and vascular endothelial cells. We have demonstrated previously that development of these lineages requires a signal(s) secreted from the adjacent primitive endoderm. We now show that Indian hedgehog (Ihh) is a primitive endoderm-secreted signal that ...

Hedgehogs are small, nocturnal mammals that become popular in the world and have significant role in transmission of zoonotic agents. Some of the agents are transmitted by ticks and fleas such as rickettsial agents. For these reason, a survey on ectoparasites in European hedgehog (Erinaceus europaeus) carried out between April 2006 and December 2007 from different parts of Urmia city, ...

Objective- The aim of this study was preparing detailed anatomic images of the thoracic cavity of the southern white-breasted hedgehog using the non-invasive computed tomography (CT) technique.Design- Descriptive study.Animals- Five southern white-breasted hedgehog (Erinaceus concolor) which is a species native to the Middle East, Anatolia, Transcaucasia, and Iran. Since some people...

Differentiation in the Drosophila eye imaginal disc traverses the disc as a wave moving from posterior to anterior. The propagation of this wave is driven by hedgehog protein secreted by the differentiated cells in the posterior region of the disc. Hedgehog induces decapentaplegic expression at the front of differentiation, in the morphogenetic furrow. We have identified a gene, shortsighted, w...

organs including the eye, hair, and lungs. Dhh and Ihh play more restricted roles: Dhh acts in the regulation of spermatogenesis and organization of the perineurium, Andrew P. McMahon Department of Molecular and Cellular Biology Harvard University Cambridge, Massachusetts 02138 which ensheaths peripheral nerves, and Ihh in coordinating proliferation and maturation of chondrocytes during develop...

Embryogenesis is mediated by a relatively small number of developmental signaling pathways, and the morphogens, receptors and transcription factors integral to these cascades are considered the master regulators of development. However, superimposed on this is an additional layer of control by complex intracellular trafficking networks. The importance of trafficking in controlling the processes...

Hedgehog and Wnt proteins are signaling molecules that direct many aspects of metazoan development through signal transduction pathways that are just beginning to be understood. Recently, the common use of glycogen synthase kinase 3 and casein kinase 1 has been added to a growing list of straightforward similarities between Hedgehog and Wnt signaling pathways. These kinases silence both pathway...

The development of the visual centers of the Drosophila brain is tightly regulated by the ingrowth of retinal axons from the developing eye. In the first optic ganglion, the lamina, arriving retinal axons trigger the precursors of their synaptic partners to complete a final cell division and commence neural differentiation. The secreted product of the hedgehog gene regulates the temporal assemb...