Netrin is a class of protein involved in axon guidance. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Axon guidance (also called axon pathfinding) is a subfield of Neural development concerning the process by which Neurons send out Axons to reach It is named after the Sanskrit word "netr", which means "one who guides. Sanskrit (sa संस्कृता वाक् saṃskṛtā vāk, for short sa संस्कृतम् saṃskṛtam) is a historical " Netrins are genetically conserved across nematode worms[1], fruitflies, frogs, and mice. Conservation refers to a high degree of similarity in orthologous DNA sequences protein sequences, or Protein structures amongst various Caenorhabditis elegans (ˌsiːnoʊræbˈdaɪtɪs ˈɛlɪgænz is a free-living Nematode (roundworm about 1 mm in length which Drosophila is a Genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" The African clawed frog ( Xenopus laevis, also known as platanna) is a species of South African aquatic Frog of the genus Xenopus The House Mouse ( Mus musculus) is one of the most numerous species of the genus Mus commonly termed a Mouse. Structurally, netrin resembles laminin. Laminin is the major non-collagenous component of the Basal lamina, such as those on which cells of an Epithelium sit
Netrins are chemotropic; a growing axon will either move towards or away from a higher concentration of netrin. Chemotropism is movement caused by chemical stimulus in organisms such as Bacteria and Plants An example of chemotropic movement can be seen during the growth of the An axon or nerve fiber is a long slender projectionof a nerve cell or Neuron, that conducts electrical impulses away from the neuron's Cell Though the detailed mechanism of axon guidance is not fully understood, it is known that netrin attraction is mediated through UNC-40/DCC cell surface receptors and repulsion is mediated through UNC-5 receptors. Axon guidance (also called axon pathfinding) is a subfield of Neural development concerning the process by which Neurons send out Axons to reach Deleted in Colorectal Carcinoma, also known as DCC, is a human gene that has long been implicated in Colorectal cancer. In Biochemistry, a receptor is a Protein molecule embedded in either the Plasma membrane or Cytoplasm of a cell to which a mobile signaling Netrins also act as growth factors, encouraging cell growth activities in target cells. The term growth factor refers to a naturally occurring Protein capable of stimulating cellular growth proliferation and Cellular differentiation. Mice deficient in netrin fail to form the hippocampal comissure or the corpus callosum. The lateral portions of the body of the Fornix are joined by a thin triangular lamina named the psalterium ( lyra) The corpus callosum is a structure of the Mammalian Brain in the longitudinal fissure that connects the left and right Cerebral hemispheres It also facilitates
A proposed model for netrin activity in the spinal column of developing human embryos is that netrins are released by the floor plate and are picked up by receptor proteins embedded in the growth cones of axons belonging to neurons in the developing spinal column. Scientific modelling is the process of generating abstract, conceptual, Graphical and or mathematical models. A vertebra (plural vertebrae) is an individual Irregular bone in the spinal or Vertebral column ( aka ischis a flexuous and flexible column An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular In the developing Nervous system, the floor plate is a Neural tube structure that separates the left and right components of the basal plate. A growth cone is a dynamic Actin -supported extension of a developing Axon seeking its synaptic target The bodies of these neurons remain stationary while the axons follow a path defined by netrins, eventually connecting to neurons inside the embryonic brain by developing synapses. Chemical synapses are specialized junctions through which Neurons signal to each other and to non-neuronal cells such as those in Muscles or Glands It seems that once a pathway has been traced by an axon, new axons tend to follow it rather than being guided by netrins or related chemotropic factors. [2]
Netrin-1
Netrin-1 is a typical member of the netrin family displaying both attractive and repulsive cues depending on context. Retinal ganglion cell (RGC) axons convey visual information from the retina to the brain via the optic nerve head (ONH) and the optic nerve. A ganglion cell (more correctly a retinal ganglion cell or RGC) is a type of Neuron typically located near the inner surface of the Retina The vertebrate retina is a light sensitive part inside the inner layer of the Eye. The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The optic disc or optic nerve head is the location where Ganglion cell axons exit the Eye to form the Optic nerve. The optic nerve, also called cranial nerve II, is the Nerve that transmits visual information from the Retina to the Brain. During embryo development, RGC axon growth follows a path to the ONH assisted by the attraction of netrin-1 expressed by ONH cells. MOrphogenesis is an EP by Industrial Black metal band.And Oceans. It is thought that the axon is then guided through the ONH to the optic nerve by repulsion induced by the presence of laminin at the ONH. Laminin is the major non-collagenous component of the Basal lamina, such as those on which cells of an Epithelium sit Evidence for this reversal in response to netrin-1 is provided by the finding that Xenopus RGC axons are repelled by netrin-1 in the presence of laminin. Xenopus (L strange foot) are a genus of Carnivorous Frog native to [3]
References
- ^ Serafini T, Kennedy TE, Galko MJ, Mirzayan C, Jessell TM, Tessier-Lavigne M. (1994) The netrins define a family of axon outgrowth-promoting proteins homologous to C. elegans UNC-6. Cell 78(3):409-24
- ^ Kennedy TE, Serafini T, de la Torre JR, Tessier-Lavigne M. (1994) Netrins are diffusible chemotropic factors for commissural axons in the embryonic spinal cord. Cell 78(3):425-35
- ^ Oster SF, Deiner M, Birgbauer E, Sretavan DW. (2004) Ganglion cell axon pathfinding in the retina and optic nerve. Semin. Cell Dev. Biol. 15:125-36
- OMIM 601614
- The Science Times Book of the Brain 1998. The Mendelian Inheritance in Man project is a Database that catalogues all the known Diseases with a genetic component, and—when possible—links them Nicholas Wade, editor. The Lyons Press.
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