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Limb Bud
The limb bud is a structure formed early in vertebrate limb development. As a result of interactions between the ectoderm and underlying mesoderm, formation occurs roughly around the fourth week of development. In the development of the human embryo the upper limb bud appears in the third week and the lower limb bud appears four days later. The limb bud consists of undifferentiated mesoderm cells that are sheathed in ectoderm. As a result of cell signaling interactions between the ectoderm and underlying mesoderm cells, formation of the developing limb bud occurs as mesenchymal cells from the lateral plate mesoderm and somites begin to proliferate to the point where they create a bulge under the ectodermal cells above. The mesoderm cells in the limb bud that come from the lateral plate mesoderm will eventually differentiate into the developing limb’s connective tissues, such as cartilage, bone, and tendon. Moreover, the mesoderm cells that come from the somites will eventually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Plate Mesoderm
The lateral plate mesoderm is the mesoderm that is found at the periphery of the embryo. It is to the side of the paraxial mesoderm, and further to the axial mesoderm. The lateral plate mesoderm is separated from the paraxial mesoderm by a narrow region of intermediate mesoderm. The mesoderm is the middle layer of the three germ layers, between the outer ectoderm and inner endoderm. During the third week of embryonic development the lateral plate mesoderm splits into two layers forming the intraembryonic coelom. The outer layer of lateral plate mesoderm adheres to the ectoderm to become the somatic or parietal layer known as the somatopleure. The inner layer adheres to the endoderm to become the splanchnic or visceral layer known as the splanchnopleure. Development The lateral plate mesoderm will split into two layers, the somatopleuric mesenchyme, and the splanchnopleuric mesenchyme. * The ''somatopleuric layer'' forms the future body wall. * The ''splanchnopleuric laye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic Hedgehog
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 activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
FGF8
Fibroblast growth factor 8 (FGF-8) is a protein that in humans is encoded by the ''FGF8'' gene. Function The protein encoded by this gene is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. FGF-8 is important and necessary for setting up and maintaining the midbrain/hindbrain border (or mesencephalon/metencephalon border) which plays the vital role of “organizer” in development, like the Spemann organizer” of the gastrulating embryo. FGF-8 is expressed in the region where Otx2 and Gbx2 cross inhibit each other and is maintained expression by this interaction. Once expressed, the Fgf8 induces other transcription factors to form cross-regulatory loops between cells, thus the border is established. Through development, the Fgf8 goes to reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WNT3
Proto-oncogene protein Wnt-3 is a protein that in humans is encoded by the ''WNT3'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba .... The WNT gene family consists of structurally related genes that encode secreted signaling proteins. These proteins have been implicated in oncogenesis and in several developmental processes, including regulation of cell fate and patterning during embryogenesis. This gene is a member of the WNT gene family. It encodes a protein showing 98% amino acid identity to mouse Wnt3 protein, and 84% to human WNT3A protein, another WNT gene product. The mouse studies show the requirement of Wnt3 in primary axis formation in the mouse. Studies of the gene expression suggest that this gene may play a key role in some cases of human breast, rectal, lung, and g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WNT2B
Protein Wnt-2b (formerly Wnt13) is a protein that in humans is encoded by the ''WNT2B'' gene. This gene encodes a member of the wingless-type MMTV integration site (WNT) family of highly conserved, secreted signaling factors. WNT family members function in a variety of developmental processes including regulation of cell growth and differentiation and are characterized by a WNT-core domain. This gene may play a role in human development as well as human carcinogenesis. This gene produces two alternative transcript variant Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be in ...s. References Further reading * * * * * * * * * {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Proliferation
Cell proliferation is the process by which ''a cell grows and divides to produce two daughter cells''. Cell proliferation leads to an exponential increase in cell number and is therefore a rapid mechanism of tissue growth. Cell proliferation requires both cell growth and cell division to occur at the same time, such that the average size of cells remains constant in the population. Cell division can occur without cell growth, producing many progressively smaller cells (as in cleavage of the zygote), while cell growth can occur without cell division to produce a single larger cell (as in growth of neurons). Thus, cell proliferation is not synonymous with either cell growth or cell division, despite the fact that these terms are sometimes used interchangeably. Stem cells undergo cell proliferation to produce proliferating "transit amplifying" daughter cells that later differentiate to construct tissues during normal development and tissue growth, during tissue regeneration aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FGF10
Fibroblast growth factor 10 is a protein that in humans is encoded by the ''FGF10'' gene. Function The protein encoded by this gene is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. Fibroblast growth factor 10 is a paracrine signaling molecule seen first in the limb bud and organogenesis development. FGF10 starts the developing of limbs and its involved in the branching of morphogenesis in multiple organs such as the lungs, skin, ear and salivary glands. During the limb development Tbx4/Tbx5 stimulate the production of FGF10 in the lateral plate mesoderm where it will create an epithelial-mesenchymal FGF signal with FGF8. This positive feedback loop will increase the amount of mesenchyme resulting in a bulge. Afterwards, FGF10 will induce the f ... [...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] |
Gene Expression
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. These products are often proteins, but in non-protein-coding genes such as transfer RNA (tRNA) and small nuclear RNA (snRNA), the product is a functional non-coding RNA. Gene expression is summarized in the central dogma of molecular biology first formulated by Francis Crick in 1958, further developed in his 1970 article, and expanded by the subsequent discoveries of reverse transcription and RNA replication. The process of gene expression is used by all known life—eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and utilized by viruses—to generate the macromolecular machinery for life. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
