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Enhanceosome
An enhanceosome is a protein complex that assembles at an enhancer region on DNA and helps to regulate the expression of a target gene. Formation Enhancers are bound by transcription activator proteins and transcriptional regulation is typically controlled by more than one activator. Enhanceosomes are formed in special cases when these activators cooperatively bind together along the enhancer sequence to create a distinct three-dimensional structure. Each enhanceosome is unique towards its specific enhancer. This assembly is facilitated by energetically favorable protein: protein and protein: DNA interactions. Therefore, all the necessary activators need to be present for the enhanceosome to be formed and able to function. Function Once the enhanceosome has been formed, it recruits coactivators and general transcription factors to the promoter region of the target gene to begin transcription. The effectiveness of this is dependent on DNA conformation. As a result, the enh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enhanceosome Vertical
An enhanceosome is a protein complex that assembles at an enhancer region on DNA and helps to regulate the expression of a target gene. Formation Enhancers are bound by transcription activator proteins and transcriptional regulation is typically controlled by more than one activator. Enhanceosomes are formed in special cases when these activators cooperatively bind together along the enhancer sequence to create a distinct three-dimensional structure. Each enhanceosome is unique towards its specific enhancer. This assembly is facilitated by energetically favorable protein: protein and protein: DNA interactions. Therefore, all the necessary activators need to be present for the enhanceosome to be formed and able to function. Function Once the enhanceosome has been formed, it recruits coactivators and general transcription factors to the promoter region of the target gene to begin transcription. The effectiveness of this is dependent on DNA conformation. As a result, the enh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enhancer (genetics)
In genetics, an enhancer is a short (50–1500 bp) region of DNA that can be bound by proteins ( activators) to increase the likelihood that transcription of a particular gene will occur. These proteins are usually referred to as transcription factors. Enhancers are ''cis''-acting. They can be located up to 1 Mbp (1,000,000 bp) away from the gene, upstream or downstream from the start site. There are hundreds of thousands of enhancers in the human genome. They are found in both prokaryotes and eukaryotes. The first discovery of a eukaryotic enhancer was in the immunoglobulin heavy chain gene in 1983. This enhancer, located in the large intron, provided an explanation for the transcriptional activation of rearranged Vh gene promoters while unrearranged Vh promoters remained inactive. Locations In eukaryotic cells the structure of the chromatin complex of DNA is folded in a way that functionally mimics the supercoiled state characteristic of prokaryotic DNA, so although the en ... [...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] |
RNA Polymerase
In molecular biology, RNA polymerase (abbreviated RNAP or RNApol), or more specifically DNA-directed/dependent RNA polymerase (DdRP), is an enzyme that synthesizes RNA from a DNA template. Using the enzyme helicase, RNAP locally opens the double-stranded DNA so that one strand of the exposed nucleotides can be used as a template for the synthesis of RNA, a process called transcription. A transcription factor and its associated transcription mediator complex must be attached to a DNA binding site called a promoter region before RNAP can initiate the DNA unwinding at that position. RNAP not only initiates RNA transcription, it also guides the nucleotides into position, facilitates attachment and elongation, has intrinsic proofreading and replacement capabilities, and termination recognition capability. In eukaryotes, RNAP can build chains as long as 2.4 million nucleotides. RNAP produces RNA that, functionally, is either for protein coding, i.e. messenger RNA (mRNA); or n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Mobility Group
High-Mobility Group or HMG is a group of chromosomal proteins that are involved in the regulation of DNA-dependent processes such as transcription, replication, recombination, and DNA repair. Families The HMG proteins are subdivided into 3 superfamilies each containing a characteristic functional domain: * HMGA – contains an AT-hook domain ** HMGA1 ** HMGA2 * HMGB – contains a HMG-box domain ** HMGB1 ** HMGB2 ** HMGB3 ** HMGB4 * HMGN – contains a nucleosomal binding domain ** HMGN1 ** HMGN2 ** HMGN3 ** HMGN4 ** HMGN5 Proteins containing any of these embedded in their sequence are known as HMG motif proteins. HMG-box proteins are found in a variety of eukaryotic organisms. They were originally isolated from mammalian cells, and named according to their electrophoretic mobility in polyacrylamide gels. Other families with HMG-box domain * SOX gene family ** Sex-Determining Region Y Protein ** SOX1, SOX2, etc. * TCF/LEF family (T cell factor/lymphoid enhancer factor fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activating Transcription Factor
Activating transcription factor, ATF, is a group of bZIP transcription factors, which act as homodimers or heterodimers with a range of other bZIP factors. First, they have been described as members of the CREB/ATF family, whereas it turned out later that some of them might be more similar to AP-1-like factors such as c-Jun or c-Fos. In general, ATFs are known to respond to extracellular signals and this suggests an important role that they have in maintaining homeostasis. Some of these ATFs, such as ATF3, ATF4, and ATF6 are known to play a role in stress responses. Another example of ATFs function would be ATFx that can suppress apoptosis. Genes include ATF1, ATF2, ATF3, ATF4, ATF5, ATF6, ATF7 Cyclic AMP-dependent transcription factor ATF-7 is a protein that in humans is encoded by the ''ATF7'' gene. Homonym In 2001, Peters et al. published a paper showing that ATF-7, a Novel bZIP Protein, interacts with PTP4A1. This ATF-7 is actu ..., ATFx. References External links ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IRF-3
Interferon regulatory factor 3, also known as IRF3, is an interferon regulatory factor. Function IRF3 is a member of the interferon regulatory transcription factor (IRF) family. IRF3 was originally discovered as a homolog of IRF1 and IRF2. IRF3 has been further characterized and shown to contain several functional domains including a nuclear export signal, a DNA-binding domain, a C-terminal IRF association domain and several regulatory phosphorylation sites. IRF3 is found in an inactive cytoplasmic form that upon serine/threonine phosphorylation forms a complex with CREBBP. The complex translocates into the nucleus for the transcriptional activation of interferons alpha and beta, and further interferon-induced genes. IRF3 plays an important role in the innate immune system's response to viral infection. Aggregated MAVS have been found to activate IRF3 dimerization. A 2015 study shows phosphorylation of innate immune adaptor proteins MAVS, STING and TRIF at a conserved pLxI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NF-κB
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellular responses to stimuli such as stress, cytokines, free radicals, heavy metals, ultraviolet irradiation, oxidized LDL, and bacterial or viral antigens. NF-κB plays a key role in regulating the immune response to infection. Incorrect regulation of NF-κB has been linked to cancer, inflammatory and autoimmune diseases, septic shock, viral infection, and improper immune development. NF-κB has also been implicated in processes of synaptic plasticity and memory. Discovery NF-κB was discovered by Ranjan Sen in the lab of Nobel laureate David Baltimore via its interaction with an 11-base pair sequence in the immunoglobulin light-chain enhancer in B cells. Later work by Alexander Poltorak and Bruno Lemaitre in mice and ''Drosophila'' frui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interferon-beta
The type-I interferons (IFN) are cytokines which play essential roles in inflammation, immunoregulation, tumor cells recognition, and T-cell responses. In the human genome, a cluster of thirteen functional IFN genes is located at the 9p21.3 cytoband over approximately 400 kb including coding genes for IFNα (''IFNA1, IFNA2, IFNA4, IFNA5, IFNA6, IFNA7, IFNA8, IFNA10, IFNA13, IFNA14, IFNA16, IFNA17'' and ''IFNA21''), IFNω (''IFNW1''), IFNɛ (''IFNE''), IFNк (''IFNK'') and IFNβ (''IFNB1''), plus 11 IFN pseudogenes. Interferons bind to interferon receptors. All type I IFNs bind to a specific cell surface receptor complex known as the IFN-α receptor (IFNAR) that consists of IFNAR1 and IFNAR2 chains. Type I IFNs are found in all mammals, and homologous (similar) molecules have been found in birds, reptiles, amphibians and fish species. Sources and functions IFN-α and IFN-β are secreted by many cell types including lymphocytes (NK cells, B-cells and T-cells), macrophages, fibr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically moder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signaling Cascade
A biochemical cascade, also known as a signaling cascade or signaling pathway, is a series of chemical reactions that occur within a biological cell when initiated by a stimulus. This stimulus, known as a first messenger, acts on a receptor that is transduced to the cell interior through second messengers which amplify the signal and transfer it to effector molecules, causing the cell to respond to the initial stimulus. Most biochemical cascades are series of events, in which one event triggers the next, in a linear fashion. At each step of the signaling cascade, various controlling factors are involved to regulate cellular actions, in order to respond effectively to cues about their changing internal and external environments. An example would be the coagulation cascade of secondary hemostasis which leads to fibrin formation, and thus, the initiation of blood coagulation. Another example, sonic hedgehog signaling pathway, is one of the key regulators of embryonic development an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
