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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. 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 involved with the development of the four heart chambers, the electrical conducting system, and the septum separating the right and left sides of the heart. ''TBX5'' is a transcription factor that codes for the protein called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-box
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. The mou ... [...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. The mou ... [...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] |
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 m ... [...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] |
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 trunk of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast Growth Factor
Fibroblast growth factors (FGF) are a family of cell signalling proteins produced by 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 lead to a range of developmental defects. These growth factors typically act as 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 are 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 also known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetra-amelia Syndrome
Tetra-amelia syndrome (''tetra-'' + '' amelia''), also called autosomal recessive tetraamelia, is an extremely rare autosomal recessive congenital disorder characterized by the absence of all four limbs. Other areas of the body are also affected by malformations, such as the face, skull, reproductive organs, anus, lungs and pelvis. The disorder can be caused by recessive mutations in the WNT3 or RSPO2 genes. Presentation Tetra-amelia syndrome is characterized by the complete absence of all four limbs. The syndrome causes severe malformations of various parts of the body, including the face and head, heart, nervous system, skeleton, and genitalia. In many cases, the lungs are underdeveloped, which makes breathing difficult or impossible. Because children with tetra-amelia syndrome have such serious medical problems, most are stillborn or die shortly after birth. Cause RSPO2 and WNT3 genes Researchers have found loss-of-function mutations in the WNT3 or the RSPO2 genes in peo ... [...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. It wasn't until 1993 that 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 transcrib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apical Ectodermal Ridge
The apical ectodermal ridge (AER) is a structure that forms from the ectodermal cells at the distal end of each limb bud and acts as a major signaling center to ensure proper development of a limb. After the limb bud induces AER formation, the AER and limb mesenchyme—including the zone of polarizing activity (ZPA)—continue to communicate with each other to direct further limb development. The position of the limb bud, and hence the AER, is specified by the expression boundaries of Hox genes in the embryonic trunk. At these positions, the induction of cell outgrowth is thought to be mediated by a positive feedback loop of fibroblast growth factors (FGFs) between the intermediate mesoderm, the lateral plate mesoderm and the surface ectoderm. FGF8 in the intermediate mesoderm signals to the lateral mesoderm, restricting the expression of FGF10 through intermediate Wnt signals. Then, FGF10 in the lateral plate mesoderm signals to the surface ectoderm to create the AER, which ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
