Transcription factor, molecule that controls the activity of a gene by determining whether the gene’s DNA (deoxyribonucleic acid) is transcribed into RNA (ribonucleic acid). The enzyme RNA polymerase catalyzes the chemical reactions that synthesize RNA, using the gene’s DNA as a template. Translation Translation Definition. Translation refers to the process of creating proteins from an mRNA. Genetic Code. When nucleic acids were discovered as the primary genetic material. TRNA Structure and Function. Transfer RNA act as adapter molecules between mRNA and amino acids.
In, 2014 Transcription FactorsTranscription factors are proteins possessing domains that bind to the DNA of promoter or enhancer regions of specific genes. They also possess a domain that interacts with RNA polymerase II or other transcription factors and consequently regulates the amount of messenger RNA (mRNA) produced by the gene.Many families of molecules act as transcription factors. Some transcription factors are general ones that are found in virtually all cells of an organism. Other transcription factors are specific for certain types of cells and stages of development. Specific transcription factors are often very important in initiating patterns of gene expression that result in major developmental changes. They typically do so by acting on promoters or enhancers to activate or repress the transcription of specific genes.
Based on their structure and how they interact with DNA, transcription factors can be subdivided into several main groups, the most important of which are introduced here. Adcock, Gaetano Caramori, in, 2009 Transcription FactorsTranscription factors are proteins that bind to DNA-regulatory sequences (enhancers and silencers), usually localized in the 5-upstream region of target genes, to modulate the rate of gene transcription. This may result in increased or decreased gene transcription, protein synthesis, and subsequent altered cellular function. Many transcription factors have now been identified and a large proportion of the human genome appears to code for these proteins. One of the most important concepts to have emerged is the demonstration that transcription factors may physically interact with each other to form homodimers or heterodimers, resulting in inhibition or enhancement of transcriptional activity at a site distinct from the consensus target for a particular transcription factor ( Fig. This then allows cross-talk between different signal transduction pathways at the level of gene expression.
Generally it is necessary to have coincident activation of several transcription factors in order to have maximal gene expression. This may explain how transcription factors that are ubiquitous may regulate particular genes in certain types of cells 4, 10. Multiple pathways mediating transcription factor modulation of inflammatory genes, (A) Inflammatory mediator signal transduction activation. The binding of cytokines, growth factors, or chemokines to their respective receptors sets in train the activation of a number of signal transduction pathways, including the receptor tyrosine kinases, mitogen-activated protein kinases (MAPKs including MEKK1 and JNK), Janus kinases (JAKs), and other kinase pathways involved in NF-κB activation. Activation of nuclear factor-κB involves phosphorylation of the inhibitory protein IκB by specific kinase(s), with subsequent ubiquitination and proteolytic degradation by the proteasome. The free NF-κB then translocates to the nucleus, where it binds to κB sites in the promoter regions of inflammatory genes.
Activation of the IκB gene results in increased synthesis of IκB to terminate the activation NF-κB. (B) JAK-STAT pathways. Cytokine binding to its receptor results in activation of JAK which phosphorylate intracellular domains of the receptor, resulting in phosphorylation of signal transduction-activated transcription factors (STATs). Activated STATs dimerize and translocate to the nucleus where they bind to recognition elements on certain genes. (C and D) Nuclear factor of activated T-cells (NF-AT) is activated via dephosphorylation by calcineurin (CaN) and translocates to the nucleus where it interacts with AP-1 to induce gene transcription.
(E) Classical mechanism of steroid action. Glucocorticoids are lipophilic molecules which diffuse readily through cell membranes to interact with cytoplasmic receptors. Upon ligand binding receptors are activated and translocate into the nucleus where they bind to specific DNA elements. The foregoing pathways can interact so that the final signal may be amplified or altered depending upon the exact combination of stimuli. The final response to each stimulus or combination of stimuli by a particular cell depends upon the receptors present in a particular cell along with the exact intracellular transduction pathway activated.The complexity of the activation pathways and their ability to engage in cross-talk enables cells to overcome inhibition of one pathway and retain a capacity to activate specific transcription factors.
This cross-talk and redundancy may also hinder the search for novel anti-inflammatory agents targeted toward transcription factor activation. Binding of transcription factors to their specific binding motifs in the promoter region may alter transcription by interacting directly with components of the basal transcription apparatus or via cofactors that link the transcription factor to the basal transcription apparatus 14. Large proteins that bind to the basal transcription apparatus bind many transcription factors and thus act as integrators of gene transcription. These coactivator molecules include CREB-binding protein (CBP), and the related p300, thus allowing complex interactions between different signaling pathways 14. Histone acetylation. DNA is wound around histone proteins to form nucleosomes and the chromatin fiber in chromosomes 15. It has long been recognized at a microscopic level that chromatin may become dense or opaque owing to the winding or unwinding of DNA around the histone core 16.
CBP, p300, and other coactivators have histone acetylase activity (HAT) which is activated by the binding of transcription factors, such as AP-1, NF-κB, and STATs ( Fig. 31.2) 14, 15. Acetylation of histone residues results in unwinding of DNA coiled around the histone core, thus opening up the chromatin structure, allowing increased transcription. Histone deacetylation by specific histone deacetylases (HDACs) reverses this process, leading to gene repression 17. Histone acetylation by proinflammatory transcription factors. In response to stress and other stimuli, such as cytokines, various second messenger systems are upregulated, leading to activation of signal-dependent transcription factors such as CREB, NF-κB, AP-1, and STAT proteins.
Binding of these factors leads to recruitment of CBP and/or other coactivators to signal-dependent promoters and acetylation of histones by an intrinsic acetylase activity (HAT). Induction of histone acetylation allows the formation of a more loosely packed nucleosome structure which enables access to TATA box-binding protein (TBP) and associated factors (TAFs) and the recruitment of further remodeling factors including switch/sucrose nonfermentable (SWI/SNF).
Remodeling thereby allows RNA polymerase II recruitment and the activation of inflammatory gene transcription. Pingzhu Zhou. Pu, in, 2012 AbstractTranscription factors regulate formation and function of the heart, and perturbation of transcription factor expression and regulation disrupts normal heart structure and function. Multiple mechanisms regulate the level and locus-specific activity of transcription factors, including transcription, translation, subcellular localization, posttranslational modifications, and context-dependent interactions with other transcription factors, chromatin remodeling enzymes, and epigenetic regulators. The zinc finger transcription factor GATA4 is among the best-studied cardiac transcriptional factors. This review focuses on molecular mechanisms that regulate GATA4 transcriptional activity in the cardiovascular system, providing a framework to investigate and understand the molecular regulation of cardiac gene transcription by other transcription factors.
Davidson, Isabelle S. Peter, in, 2015 2.1 Basic facts about transcription factorsTranscription factors are encoded by a unique class of genes amounting in the animal genome to only a few percent of the total number of protein-coding genes. In this book, transcription factors are defined strictly as proteins that recognize and bind to specific short DNA sequences, such that their interaction with these sequences, causally affects expression of genes. The recognition of DNA sequence by transcription factors occurs by chemical interactions of the amino acid side chains of the transcription factor protein with base pair residues of DNA functioning as regulatory sequence. The transcription factors thus “read” the genomic sequence, and the most fundamental fact about this mechanism is that it is the sequence recognition function on which informational aspects of all regulatory transactions controlling gene expression depend.
Only a relatively small, finite number of protein structural motifs have evolved which have the capacity to recognize and bind to specific DNA sequence. With few exceptions, all animals utilize the same families of transcription factors, representatives of which were evidently present in their common evolutionary ancestor. Transcription factors consist of DNA-binding domains by which these families are defined and effector domains that mediate interactions with other proteins necessary for transcription, and with other transcription factors. The DNA-binding domains are typically highly conserved per family across the Animal Kingdom, while the effector domains evolve more rapidly. Transcription factors execute many functions as we shall see in the course of this book, including gene activation, gene repression, and signal response.
They function as diffusible regulatory molecules, that is, they are transcribed in the nucleus, translated in the cytoplasm, and find their target sites in the genomic DNA on reentry into the nucleus, mediated by nuclear localization sites included in all transcription factor protein sequences. Transcription factor presence in a particular cell in development depends on regulation of the genes encoding them. This is consequently the key primary locus of control in development.
Transcription factor occupancy of their target sites depends on two parameters, as we examine in detail in Chapter 2: the intrinsic tightness of binding between the transcription factor protein and the DNA target site, and the concentration at which the transcription factor is present in the nucleus. Quantitative and biochemical studies have shown that an important and general aspect of transcription factor–DNA interaction is that all transcription factors include basic domains which cause them to be concentrated nonspecifically in the vicinity of the DNA, facilitating the diffusion-limited discovery of their target sites. The most important general principle of transcription factor regulatory function in animal cells is that they never work alone, but always together with other specifically bound transcription factors and cofactors, since regulation of transcription requires a multiplicity of biochemical effector functions. Alberini, in, 2009Transcription factors are proteins that bind specific sites or elements in regulatory regions of DNA, known as promoters or enhancers, where they control the transcription or expression of target genes. Transcription factors can be selectively activated or deactivated by other proteins, often as the final step in signal transduction. There are three functional classes of transcription factors: (1) general transcription factors, which are ubiquitous and represent the core machinery of transcription; the most common are abbreviated as TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH; (2) constitutively expressed factors that in each cell type constitutively stimulate or repress transcription; and (3) inducible transcription factors, which are similar to the constitutively expressed transcription factors but require activation or inhibition. Transcription factors are composed of two essential functional regions: a DNA-binding domain and an activator domain.
The DNA-binding domain consists of amino acids that recognize specific DNA bases on the regulatory element. Watson, in, 2013 9.1 Therapeutic targeting of ETS transcription factorsTargeting transcription factors for therapeutic gain is the focus of intense research as being able to manipulate transcriptional expression patterns would provide a novel approach for the treatment of many human diseases. The primary limitations to targeting transcription factors are the potential for off-target effects and insufficient delivery within the cell. Overwhelming evidence suggests that the number of transcription factors whose aberrant function supports tumorigenesis is limited ( Darnell, 2002). Additionally, this limited number of transcription factors function at critical focal points controlling many of the genes involved in cancer-associated processes.
Therefore, targeting transcription factors has great potential for therapeutic gain. A transcription factor is a protein that binds to specific DNA sequences and contributes to modulation of gene expression. Transcription factors are the key determinants of the epigenetic state of the cell. They are modular in structure and contain the following domains:.A DNA-binding domain (DBD), having high affinity for specific sequences of DNA.A trans-activating domain (TAD) or trans-repressive domain (TRD), mediating protein–protein interactions with transcriptional coregulators.An optional signal-sensing domain (SSD) (e.g., a ligand binding domain), which can modulate DNA-binding and/or protein-binding activity in response to cellular cuesDNA sequences having high affinity for transcription factor binding are often referred to as response elements.
Transcription factor binding to accessible promoters and enhancers recruits additional proteins, such as coactivators/corepressors, chromatin remodelers, histone-modifying enzymes, and RNA polymerases, to modulate gene expression.Although sequence-specific DNA binding is a defining feature of transcription factors, chromatin accessibility is a key determinant of transcription factor binding. Most transcription factors preferentially bind nucleosome-free DNA. In many cases, a transcription factor needs to compete for DNA binding with other transcription factors, histones, and nonhistone chromatin proteins. The competitive balance between nucleosome and transcription factor binding is critically affected by chromatin remodeling complexes (see later). In practice, only a small fraction of potential response elements is actually bound, and many experimentally detected transcription factor binding sites (TFBS) lack canonical response elements. The genome-wide pattern of transcription factor binding can be determined experimentally using chromatin immunoprecipitation (ChIP) and next-generation sequencing (ChIP-Seq; see later) and is known as the transcription factor cistrome.Different cell types typically express both common and distinct transcription factors.
Moreover, the cistrome of a transcription factor differs among cell types, reflecting differences in chromatin accessibility and helping to define active promoters and enhancers. Master transcription factors are a special subset of lineage-defining transcription factors having expression restricted to specific cell types and demonstrating very high binding at superenhancers. Gurdon, in, 2016 AbstractTranscription factors fulfill a key role in the formation and maintenance of different cell-types during development. It is known that transcription factors largely dissociate from chromosomes during mitosis. We found, previously, that mitosis is also a time when somatic nuclei can be far more easily reprogrammed after nuclear transfer than the nuclei of interphase cells.
We refer to this as a mitotic advantage. Here, the rate of exchange of a transcription factor on its designated DNA-binding site is discussed. It is proposed that the Xenopus oocyte could serve as an experimental system in which the duration of binding site occupancy could be usefully analyzed. In particular, the Xenopus oocyte has several characteristics which make it possible to determine accurately the concentration and duration of transcription factor binding. It is proposed that the concentration and time are the key variables which govern the action of transcription factors when they activate genes needed for cell lineage determination.
Latchman, in, 2008 7.1 TRANSCRIPTION FACTOR REGULATIONTranscription factors play a central role in a number of biological processes, producing, for example, the induction of specific genes in response to particular stimuli as well as controlling the cell type specific or developmentally regulated expression of other genes. The ability to bind to DNA ( Chapter 4) and influence the rate of transcription either positively ( Chapter 5) or negatively ( Chapter 6) are clearly features of many transcription factors which regulate gene expression in response to specific stimuli or in specific cell types. Most importantly, however, such factors must also have their activity regulated such that they only become active in the appropriate cell type or in response to the appropriate stimulus, thereby producing the desired pattern of gene expression. Two basic mechanisms by which the action of transcription factors can be regulated have been described.
These involve either controlling the synthesis of the transcription factor so that it is made only when necessary ( Fig. 7.1a) or, alternatively, regulating the activity of the factor so that pre-existing protein becomes activated when required ( Fig. This chapter considers the regulation of transcription factor synthesis whilst Chapter 8 considers the regulation of transcription factor activity.
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Related to transcription: phonetic transcription
tran·scrip·tion
(trăn-skrĭp′shən)n.2. Something that has been transcribed, especially:
b. A recorded radio or television program.
c. Linguistics A representation of speech sounds in phonetic symbols.
3. Genetics The synthesis of messenger RNA from a DNA template through the formation of base pairs, resulting in a transfer of genetic information that codes for amino acid sequences composing proteins.
tran·scrip′tion·al·ly adv.
transcription
(trænˈskrɪpʃən) n1. the act or an instance of transcribing or the state of being transcribed
3. (Phonetics & Phonology) a representation in writing of the actual pronunciation of a speech sound, word, or piece of continuous text, using not a conventional orthography but a symbol or set of symbols specially designated as standing for corresponding phonetic values
tranˈscriptionally, tranˈscriptivelyadv
tran•scrip•tion
(trænˈskrɪp ʃən)n.
2. something transcribed.
4. the arrangement of a musical composition for a medium other than that for which it was orig. written.
5. a recording made esp. for broadcasting on radio or television.
6. Genetics. the process by which messenger RNA is synthesized on a template of DNA.
[1590–1600; < Latin trānscrīptiō. See transcript, -tion]
tran·scrip·tion
(trăn-skrĭp′shən) The process in a cell by which genetic material is copied from a strand of DNA to a complementary strand of RNA (called messenger RNA). Transcription takes place in the nucleus before messenger RNA is transported to the ribosomes, the places in the cell where proteins are made.
Noun | 1. | transcription - something written, especially copied from one medium to another, as a typewritten version of dictation black and white, written communication, written language - communication by means of written symbols (either printed or handwritten) transliteration - a transcription from one alphabet to another phonetic transcription - a transcription intended to represent each distinct speech sound with a separate symbol |
2. | transcription - (genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA; the process whereby a base sequence of messenger RNA is synthesized on a template of complementary DNA genetic science, genetics - the branch of biology that studies heredity and variation in organisms biological process, organic process - a process occurring in living organisms | |
3. | transcription - a sound or television recording (e.g., from a broadcast to a tape recording) recording - a storage device on which information (sounds or images) have been recorded | |
4. | transcription - the act of arranging and adapting a piece of music rearrangement - changing an arrangement orchestration, instrumentation - the act of arranging a piece of music for an orchestra and assigning parts to the different musical instruments orchestration - an arrangement of events that attempts to achieve a maximum effect; 'the skillful orchestration of his political campaign' | |
5. | transcription - the act of making a record (especially an audio record); 'she watched the recording from a sound-proof booth' creating from raw materials - the act of creating something that is different from the materials that went into it lip sync, lip synch, lip synchronisation, lip synchronization - combining audio and video recording in such a way that the sound is perfectly synchronized with the action that produced it; especially synchronizing the movements of a speaker's lips with the sound of his speech mastering - the act of making a master recording from which copies can be made; 'he received a bill for mastering the concert and making 100 copies' prerecord - record before presentation, as of a broadcast accession - make a record of additions to a collection, such as a library delete, erase - wipe out digitally or magnetically recorded information; 'Who erased the files form my hard disk?' record, enter, put down - make a record of; set down in permanent form |
transkripce
転写
transcription
[trænˈskrɪpʃən]N (gen) → transcripciónfphonetic transcription → pronunciaciónffonética
transcription
n (Mus, Phon) → Transkriptionf; (= copy, of shorthand notes) → Abschriftf; (= act) → Abschriftf, → Abschreibennt; (of speech, proceedings) → Niederschriftf, → Protokollnt; (Rad, TV: = recording) → Aufnahmef; phonetic transcription → Lautschriftf, → phonetische (Um)schrift
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