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Repulsive Guidance Molecule
Repulsive guidance molecules (RGMs) are members of a three gene family (in vertebrates) composed of RGMa, RGMb, and RGMc (also called hemojuvelin). RGMa has been implicated to play an important role in the developing brain and in the scar tissue that forms after a brain injury. For example, RGMa helps guide retinal ganglion cell (RGC) axons to the tectum in the midbrain. It has also been demonstrated that after induced spinal cord injury RGMa accumulates in the scar tissue around the lesion. Further research has shown that RGMa is an inhibitor of axonal outgrowth. Taken together, these findings highlight the importance of RGMa in axonal guidance Axon guidance (also called axon pathfinding) is a subfield of neural development concerning the process by which neurons send out axons to reach their correct targets. Axons often follow very precise paths in the nervous system, and how they man ... and outgrowth. Family members References {{DEFAULTSORT:Repulsive Guidance Molec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Family
A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. One such family are the genes for human hemoglobin subunits; the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci. These two gene clusters are thought to have arisen as a result of a precursor gene being duplicated approximately 500 million years ago. Genes are categorized into families based on shared nucleotide or protein sequences. Phylogenetic techniques can be used as a more rigorous test. The positions of exons within the coding sequence can be used to infer common ancestry. Knowing the sequence of the protein encoded by a gene can allow researchers to apply methods that find similarities among protein sequences that provide more information than similarities or differences among DNA sequences. If the genes of a gene family encode proteins, the term '' protein family'' is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGMA
Repulsive guidance molecule A (RGMa) is a bone morphogenetic protein (BMP) co-receptor of the repulsive guidance molecule family. Together with BMPR1A and BMPR1B, as well as ACVR2A and BMPR2, it binds BMPs thereby activating the intracellular SMAD1/5/8 signalling pathway. In humans this protein is encoded by the ''RGMA'' gene. Function RGMa is a repulsive guidance molecule for retinal axons. Furthermore, neogenin functions as a receptor for RGM. Neogenin overexpression and RGM downexpression in the developing embryonic neural tube induces apoptosis. The apoptotic activity of neogenin in the neural tube is associated with cleavage of its cytoplasmic domain by caspases. RGMA belongs to a family of repulsive guidance molecules that are (glycosylphosphatidylinositol)-linked cell-membrane-associated proteins. The three proteins, RGMa (this protein), RGMb and RGMc are 40-50% identical to each other, and share similarities in predicted protein domains and overall structure. All t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGMB
Repulsive guidance molecule B (RGMb), also known as DRAGON (DRG11-responsive axonal guidance and outgrowth of neurite), is a bone morphogenetic protein (BMP) co-receptor of the repulsive guidance molecule family. In humans this protein is encoded by the ''RGMB'' gene. Function RGMB is a glycosylphosphatidylinositol (GPI)-anchored member of the repulsive guidance molecule family (see also RGMA and RGMC) and contributes to the patterning of the developing nervous system. There is a potential association between RGMs and cancer bone metastasis, as RGMs coordinate bone morphogenetic protein (BMP) signaling. RGMB may act as a negative regulator ''in vitro'' in breast cancer and prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that sur ... through BMP signalling. Furthermore, ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemojuvelin
Hemojuvelin (HJV), also known as repulsive guidance molecule C (RGMc) or hemochromatosis type 2 protein (HFE2), is a membrane-bound and soluble protein in mammals that is responsible for the iron overload condition known as juvenile hemochromatosis in humans, a severe form of hemochromatosis. In humans, the hemojuvelin protein is encoded by the ''HFE2'' gene. Hemojuvelin is a member of the repulsive guidance molecule family of proteins. Both RGMa and RGMb are found in the nervous system, while hemojuvelin is found in skeletal muscle and the liver. Function For many years the signal transduction pathways that regulate systemic iron homeostasis have been unknown. However it has been demonstrated that hemojuvelin interacts with bone morphogenetic protein (BMP), possibly as a co-receptor, and may signal via the SMAD pathway to regulate hepcidin expression. Associations with BMP2 and BMP4 have been described. Mouse HJV knock-out models confirmed that HJV is the gene responsib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Development
The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The field of neural development draws on both neuroscience and developmental biology to describe and provide insight into the cellular and molecular mechanisms by which complex nervous systems develop, from nematodes and fruit flies to mammals. Defects in neural development can lead to malformations such as holoprosencephaly, and a wide variety of neurological disorders including limb paresis and paralysis, balance and vision disorders, and seizures, and in humans other disorders such as Rett syndrome, Down syndrome and intellectual disability. Overview of vertebrate brain development The vertebrate central nervous system (CNS) is derived from the ectoderm—the outermost germ layer of the embryo. A part of the dorsal ectoderm becomes speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granulation Tissue
Granulation tissue is new connective tissue and microscopic blood vessels that form on the surfaces of a wound during the healing process. Granulation tissue typically grows from the base of a wound and is able to fill wounds of almost any size. Examples of granulation tissue can be seen in pyogenic granulomas and pulp polyps. Its histological appearance is characterized by proliferation of fibroblasts and new thin-walled, delicate capillaries (angiogenesis), infiltrated inflammatory cells in a loose extracellular matrix. Appearance During the migratory phase of wound healing, granulation tissue is: * light red or dark pink, being perfused with new capillary loops or "buds"; * soft to the touch; * moist; * bumpy (granular) in appearance, due to punctate hemorrhages; * pulsatile on palpation; * painless when healthy; Structure Granulation tissue is composed of tissue matrix supporting a variety of cell types, most of which can be associated with one of the following functions: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traumatic Brain Injury
A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic brain injury), mechanism ( closed or penetrating head injury), or other features (e.g., occurring in a specific location or over a widespread area). Head injury is a broader category that may involve damage to other structures such as the scalp and skull. TBI can result in physical, cognitive, social, emotional and behavioral symptoms, and outcomes can range from complete recovery to permanent disability or death. Causes include falls, vehicle collisions and violence. Brain trauma occurs as a consequence of a sudden acceleration or deceleration within the cranium or by a complex combination of both movement and sudden impact. In addition to the damage caused at the moment of injury, a variety of events following the injury may result in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinal Ganglion Cell
A retinal ganglion cell (RGC) is a type of neuron located near the inner surface (the ganglion cell layer) of the retina of the human eye, eye. It receives visual information from photoreceptor cell, photoreceptors via two intermediate neuron types: Bipolar cell of the retina, bipolar cells and retina amacrine cells. Retina amacrine cells, particularly narrow field cells, are important for creating functional subunits within the ganglion cell layer and making it so that ganglion cells can observe a small dot moving a small distance. Retinal ganglion cells collectively transmit image-forming and non-image forming visual information from the retina in the form of action potential to several regions in the thalamus, hypothalamus, and mesencephalon, or midbrain. Retinal ganglion cells vary significantly in terms of their size, connections, and responses to visual stimulation but they all share the defining property of having a long axon that extends into the brain. These axons form th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axon
An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons (pseudounipolar neurons), such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. Axon dysfunction can be the cause of many inherited and acquired neurological disorders that affect both the peripheral and central neurons. Nerve fibers are classed into three typesgroup A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C are unmyelinated. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midbrain Tectum
The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', "middle", and ''enkephalos'', "brain". Structure The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. Rostrally the midbrain adjoins the diencephalon (thalamus, hypothalamus, etc.), while caudally it adjoins the hindbrain (pons, medulla and cerebellum). In the rostral direction, the midbrain noticeably splays laterally. Sectioning of the midbrain is usually performed axially, at one of two levels – that of the superior colliculi, or that of the inferior colliculi. One common technique for remembering the structures of the midbrain involves visualizing these cross-sections (especially at the level of the superior colliculi) as the upside-down face of a bear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesencephalon
The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', "middle", and ''enkephalos'', "brain". Structure The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. Rostrally the midbrain adjoins the diencephalon (thalamus, hypothalamus, etc.), while caudally it adjoins the hindbrain (pons, medulla and cerebellum). In the rostral direction, the midbrain noticeably splays laterally. Sectioning of the midbrain is usually performed axially, at one of two levels – that of the superior colliculi, or that of the inferior colliculi. One common technique for remembering the structures of the midbrain involves visualizing these cross-sections (especially at the level of the superior colliculi) as the upside-down face of a bea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Cord Injury
A spinal cord injury (SCI) is damage to the spinal cord that causes temporary or permanent changes in its function. Symptoms may include loss of muscle function, sensation, or autonomic function in the parts of the body served by the spinal cord below the level of the injury. Injury can occur at any level of the spinal cord and can be ''complete'', with a total loss of sensation and muscle function at lower sacral segments, or ''incomplete'', meaning some nervous signals are able to travel past the injured area of the cord up to the Sacral S4-5 spinal cord segments. Depending on the location and severity of damage, the symptoms vary, from numbness to paralysis, including bowel or bladder incontinence. Long term outcomes also range widely, from full recovery to permanent tetraplegia (also called quadriplegia) or paraplegia. Complications can include muscle atrophy, loss of voluntary motor control, spasticity, pressure sores, infections, and breathing problems. In the majority of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
