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TBX5
T-box transcription factor TBX5, (T-box protein 5) is a protein that in humans is encoded by the ''TBX5'' gene. Abnormalities in the TBX5 gene can result in altered limb development, Holt-Oram syndrome, Tetra-amelia syndrome, and cardiac and skeletal problems. This gene is a member of a phylogenetically conserved family of genes that share a common DNA-binding domain, the T-box. T-box genes encode transcription factors involved in the regulation of developmental processes. This gene is closely linked to related family member T-box 3 (ulnar mammary syndrome) on human chromosome 12. ''TBX5'' is located on the long arm of chromosome 12. ''TBX5'' produces a protein called T-box protein 5 that acts as a transcription factor. ''TBX5'' is involved with forelimb and heart development. This gene impacts the early development of the forelimb by triggering fibroblast growth factor, FGF10. Function ''TBX5'' is a transcription factor that codes for the protein called T-box 5. The tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-box
T-box refers to a group of transcription factors involved in embryo, embryonic limb development, limb and heart development. Every T-box protein has a relatively large DNA-binding domain, generally comprising about a third of the entire protein that is both necessary and sufficient for sequence-specific DNA binding. All members of the T-box gene family bind to the "T-box", a DNA consensus sequence of TCACACCT. Members T-boxes are especially important to the development of embryos, found in zebrafish oocyte by Bruce et al 2003 and ''Xenopus laevis'' oocyte by Xanthos et al 2001. They are also gene expression, expressed in later stages, including adult mouse and rabbit studied by Szabo et al 2000. Mutations in the first one found caused short tails in mice, and thus the protein encoded was named brachyury, Greek for "short-tail". In mice this gene is named ''Tbxt'', and in humans it is named ''T-box transcription factor T, TBXT''. Brachyury has been found in all bilaterian animal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tbx4
T-box refers to a group of transcription factors involved in embryonic limb and heart development. Every T-box protein has a relatively large DNA-binding domain, generally comprising about a third of the entire protein that is both necessary and sufficient for sequence-specific DNA binding. All members of the T-box gene family bind to the "T-box", a DNA consensus sequence of TCACACCT. Members T-boxes are especially important to the development of embryos, found in zebrafish oocyte by Bruce et al 2003 and '' Xenopus laevis'' oocyte by Xanthos et al 2001. They are also expressed in later stages, including adult mouse and rabbit studied by Szabo et al 2000. Mutations in the first one found caused short tails in mice, and thus the protein encoded was named brachyury, Greek for "short-tail". In mice this gene is named ''Tbxt'', and in humans it is named '' TBXT''. Brachyury has been found in all bilaterian animals that have been screened, and is also present in the cnidaria. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NKX2-5
Homeobox protein Nkx-2.5 is a protein that in humans is encoded by the ''NKX2-5'' gene. Function Homeobox-containing genes play critical roles in regulating tissue-specific gene expression essential for tissue differentiation, as well as determining the temporal and spatial patterns of development (Shiojima et al., 1995). It has been demonstrated that a ''Drosophila'' homeobox-containing gene called 'tinman' is expressed in the developing dorsal vessel and in the equivalent of the vertebrate heart. Mutations in tinman result in loss of heart formation in the embryo, suggesting that tinman is essential for ''Drosophila'' heart formation. Furthermore, abundant expression of Csx, the presumptive mouse homolog of tinman, is observed only in the heart from the time of cardiac differentiation. CSX, the human homolog of murine Csx, has a homeodomain sequence identical to that of Csx and is expressed only in the heart, again suggesting that CSX plays an important role in human heart for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holt–Oram Syndrome
Holt–Oram syndrome (also called atrio-digital syndrome, atriodigital dysplasia, cardiac-limb syndrome, heart-hand syndrome type 1, HOS, ventriculo-radial syndrome) is an autosomal dominant disorder that affects bones in the arms and hands (the upper limbs) and often causes heart problems. The syndrome may include an absent radial bone in the forearm, an atrial septal defect in the heart, or heart block. It affects approximately 1 in 100,000 people. Presentation All people with Holt-Oram syndrome have at least one abnormal wrist bone, which can often only be detected by X-ray. Other bone abnormalities are associated with the syndrome. These vary widely in severity, and include a missing thumb, a thumb that looks like a finger, upper arm bones of unequal length or underdeveloped, partial or complete absence of bones in the forearm, and abnormalities in the collar bone or shoulder blade. Bone abnormalities may affect only one side of the body or both sides; if both sides ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GATA4
Transcription factor GATA-4 is a protein that in humans is encoded by the ''GATA4'' gene. Function This gene encodes a member of the GATA family of zinc finger transcription factors. Members of this family recognize the GATA motif which is present in the promoters of many genes. This protein is thought to regulate genes involved in embryogenesis and in myocardial differentiation and function. Mutations in this gene have been associated with cardiac septal defects as well as reproductive defects. GATA4 is a critical transcription factor for proper mammalian cardiac development and essential for survival of the embryo. GATA4 works in combination with other essential cardiac transcription factors as well, such as Nkx2-5 and Tbx5. GATA4 is expressed in both embryo and adult cardiomyocytes where it functions as a transcriptional regulator for many cardiac genes, and also regulates hypertrophic growth of the heart. GATA4 promotes cardiac morphogenesis, cardiomyocytes survival, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domestic Pigeon
The domestic pigeon (''Columba livia domestica'' or ''Columba livia'' Form (zoology), forma ''domestica'') is a pigeon subspecies that was derived from the rock dove, rock dove or rock pigeon. The rock pigeon is the world's oldest domesticated bird. Mesopotamian Cuneiform script, cuneiform tablets mention the domestication of pigeons more than 5,000 years ago, as do Egyptian hieroglyphics. Pigeons have held historical importance to humans as Squab, food, Companion animal, pets, Doves as symbols, holy animals, and Carrier Pigeon, messengers. Due to their homing ability, pigeons have been used to deliver messages, including War pigeon, during the world wars. Despite this, city pigeons, which are feral birds, are generally seen as Pest (organism), pests, mainly due to their feces, droppings and a reputation for Natural reservoir, spreading disease. History of domestication Despite the long history of pigeons, little is known about the specifics of their initial domestication. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limb Development
Limb development in vertebrates is an area of active research in both developmental and evolutionary biology, with much of the latter work focused on the transition from fin to limb. Limb formation begins in the morphogenetic limb field, as mesenchymal cells from the lateral plate mesoderm proliferate to the point that they cause the ectoderm above to bulge out, forming a limb bud. Fibroblast growth factor (FGF) induces the formation of an organizer at the end of the limb bud, called the apical ectodermal ridge (AER), which guides further development and controls cell death. Programmed cell death is necessary to eliminate webbing between digits. The limb field is a region specified by expression of certain Hox genes, a subset of homeotic genes, and T-box transcription factors – Tbx5 for forelimb or wing development, and Tbx4 for leg or hindlimb development. Establishment of the forelimb field (but not hindlimb field) requires retinoic acid signaling in the developing trun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast Growth Factor
Fibroblast growth factors (FGF) are a family of cell signalling proteins produced by the macrophages. They are involved in a wide variety of processes, most notably as crucial elements for normal development in animal cells. Any irregularities in their function will lead to a range of developmental defects. These growth factors typically act as a systemic or locally circulating molecules of extracellular origin that activate cell surface receptors. A defining property of FGFs is that they bind to heparin and to heparan sulfate. Thus, some are sequestered in the extracellular matrix of tissues that contains heparan sulfate proteoglycans, and released locally upon injury or tissue remodeling. Families In humans, 23 members of the FGF family have been identified, all of which are ''structurally'' related signaling molecules: * Members FGF1 through FGF10 all bind fibroblast growth factor receptors (FGFRs). FGF1 is also known as ''acidic fibroblast growth factor'', and FGF2 is al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phocomelia
Phocomelia is a congenital condition that involves malformations of human arms and legs which result in a flipper-like appendage. A prominent cause of phocomelia is the mother being prescribed the use of the drug thalidomide during pregnancy; however, the causes of most cases are to be determined. Occurrence in an individual results in various abnormalities to the face, limbs, ears, nose, vessels and many other underdevelopments. Although operations may improve some abnormalities, many are not surgically treatable due to the lack of nerves and other related structures. The term is from Ancient Greek φώκη ''phōkē'', " seal (animal)" + ''-o-'' interfix + μέλος ''melos'', "limb" + ια ''-ia'' suffix). Phocomelia is an extremely rare congenital disorder involving malformation of the limbs ( dysmelia). Étienne Geoffroy Saint-Hilaire coined the term in 1836. Signs and symptoms The symptoms of phocomelia syndrome are undeveloped limbs and absent pelvic bones; however, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knockout Mouse
A knockout mouse, or knock-out mouse, is a genetically modified mouse (''Mus musculus'') in which researchers have inactivated, or " knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are important animal models for studying the role of genes which have been sequenced but whose functions have not been determined. By causing a specific gene to be inactive in the mouse, and observing any differences from normal behaviour or physiology, researchers can infer its probable function. Mice are currently the laboratory animal species most closely related to humans for which the knockout technique can easily be applied. They are widely used in knockout experiments, especially those investigating genetic questions that relate to human physiology. Gene knockout in rats is much harder and has only been possible since 2003. The first recorded knockout mouse was created by Mario R. Capecchi, Martin Evans, and Oliver Smithies in 1989, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zone Of Polarizing Activity
The zone of polarizing activity (ZPA) is an area of mesenchyme that contains signals which instruct the developing limb bud to form along the anterior/posterior axis. Limb bud is undifferentiated mesenchyme enclosed by an ectoderm covering. Eventually, the limb bud develops into bones, tendons, muscles and joints. Limb bud development relies not only on the ZPA, but also many different genes, signals, and a unique region of ectoderm called the apical ectodermal ridge (AER). Research by Saunders and Gasseling in 1948 identified the AER and its subsequent involvement in proximal distal outgrowth. Twenty years later, the same group did transplantation studies in chick limb bud and identified the ZPA. In 1993, Todt and Fallon showed that the AER and ZPA are dependent on each other. Patterning Patterning along the limb bud requires signals from many sources. Specifically, proteins called transcription factors (TF) help control the rate at which a gene is transcribed. The limb bud ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
