Sonic hedgehog protein (SHH) is encoded for by the SHH gene. The protein is named after the character Sonic the Hedgehog.
This signaling molecule is key in regulating embryonic morphogenesis in all animals. SHH controls organogenesis and the organization of the central nervous system, limbs, digits and many other parts of the body. Sonic hedgehog is a morphogen that patterns the developing embryo using a concentration gradient characterized by the French flag model. This model has a non-uniform distribution of SHH molecules which governs different cell fates according to concentration. Mutations in this gene can cause holoprosencephaly, a failure of splitting in the cerebral hemispheres, as demonstrated in an experiment using SHH knock-out mice in which the forebrain midline failed to develop and instead only a single fused telencephalic vesicle resulted.
Sonic hedgehog still plays a role in differentiation, proliferation, and maintenance of adult tissues. Abnormal activation of SHH signaling in adult tissues has been implicated in various types of cancers including breast, skin, brain, liver, gallbladder and many more.
The hedgehog gene (hh) was first identified in the fruit fly Drosophila melanogaster in the classic Heidelberg screens of Christiane Nüsslein-Volhard and Eric Wieschaus, as published in 1980. These screens, which led to the researchers winning a Nobel Prize in 1995 along with developmental geneticist Edward B. Lewis, identified genes that control the segmentation pattern of the Drosophila embryos. The hh loss of function mutant phenotype causes the embryos to be covered with denticles, i.e. small pointy projections resembling the spikes of a hedgehog. Investigations aimed at finding a hedgehog equivalent in vertebrates by Philip Ingham, Andrew P. McMahon and Clifford Tabin revealed three homologous genes.
Two of these genes, desert hedgehog and Indian hedgehog, were named for species of hedgehogs, while sonic hedgehog was named after the video game character Sonic the Hedgehog.
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Students will learn essentials of cell and developmental biology with an engineering mind set, with an emphasis on animal model systems and quantitative approaches.
Tissue engineering is an interdisciplinary field that broadly impacts human health. This course provides students an overview of how engineering approaches can be used to investigate and manipulate ce
The Hedgehog signaling pathway is a signaling pathway that transmits information to embryonic cells required for proper cell differentiation. Different parts of the embryo have different concentrations of hedgehog signaling proteins. The pathway also has roles in the adult. Diseases associated with the malfunction of this pathway include cancer. The Hedgehog signaling pathway is one of the key regulators of animal development and is present in all bilaterians.
The Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt is a portmanteau created from the names Wingless and Int-1. Wnt signaling pathways use either nearby cell-cell communication (paracrine) or same-cell communication (autocrine). They are highly evolutionarily conserved in animals, which means they are similar across animal species from fruit flies to humans.
Polydactyly or polydactylism (), also known as hyperdactyly, is an anomaly in humans and animals resulting in supernumerary fingers and/or toes. Polydactyly is the opposite of oligodactyly (fewer fingers or toes). As of 1977, the incidence of congenital deformities in newborns was approximately 2%, and 10% of these deformities involve the upper extremity. In 1961, Frantz and O’Rahilly proposed, that congenital anomalies of the limb could be classified in seven categories, based on the embryonic failure causing the clinical presentation.
This course will provide the fundamental knowledge in neuroscience required to
understand how the brain is organised and how function at multiple scales is
integrated to give rise to cognition and beh
This course will provide the fundamental knowledge in neuroscience required to
understand how the brain is organised and how function at multiple scales is
integrated to give rise to cognition and beh
This course will provide the fundamental knowledge in neuroscience required to
understand how the brain is organised and how function at multiple scales is
integrated to give rise to cognition and beh
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Human embryonic stem cell-derived retinal pigment epithelial cells (hESC-RPE) are a promising cell source to treat age-related macular degeneration (AMD). Despite several ongoing clinical studies, a detailed mapping of transient cellular states during in v ...
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Humans and other tetrapods are considered to require apical-ectodermal-ridge (AER) cells for limb development, and AER-like cells are suggested to be re-formed to initiate limb regeneration. Paradoxically, the presence of AER in the axolotl, a primary mode ...