| transcription factor | <molecular biology> Protein required for recognition by RNA polymerases of specific stimulatory sequences in eukaryotic genes. Several are known that activate transcription by RNA polymerase II when bound to upstream promoters. Transcription of the 5S RNA gene in Xenopus by RNA polymerase III is dependent on a 40 kD protein TFIIIA that binds to a regulatory site in the centre of the gene and was the first protein found to exhibit the metal binding domains known as zinc fingers. (17 Mar 1998) |
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| transcription factor ap-1 | A multiprotein complex composed of the products of c-jun and c-fos proto-oncogenes. These proteins must dimerise in order to bind to the ap-1 recognition site, also known as the tpa-responsive element (tre). Ap-1 controls both basal and inducible transcription of several genes. (12 Dec 1998) |
| transcription factor, sp1 | Promoter-specific RNA polymerase II transcription factor that binds to the gc box, one of the upstream promoter elements (upe) in mammalian cells. The binding of sp1 is necessary to initiate transcription in the promoters of a variety of cellular and viral genes including c-ha-ras and HIV. (12 Dec 1998) |
| erythroid transcription factor | <molecular biology> Transcription factor that binds to regulatory regions of genes expressed in erythroid cells. (18 Nov 1997) |
| macrophage-activating factor | An agent that stimulates macrophages to attack and ingest cancer cells. They are secreted by stimulated lymphocytes that prime macrophages to become non-specifically cytotoxic to tumours. They also modulate the expression of macrophage cell surface ia antigens. One maf is interferon-gamma (interferon type II). Other factors antigenically distinct from ifn-gamma have also been identified. (12 Dec 1998) |
| monocyte chemotactic and activating factor | Cytokine of the C C subfamily, co induced with IL-8 on stimulation of endothelial cells, fibroblasts or monocytes that activates and is chemotactic for, monocytes. A chemokine. (18 Nov 1997) |
| platelet-activating factor | <cytokine> Potent phospholipid activator and mediator of many leucocyte functions, including platelet aggregation, inflammation, and anaphylaxis. It is produced in response to specific stimuli by a variety of cell types, including neutrophils, basophils, platelets, and endothelial cells. Several molecular species of platelet-activating factor have been identified which vary in the length of the O-alkyl side chain. It is an important mediator of bronchoconstriction. Synonym: platelet-aggregating factor. Acronym: PAF (20 Sep 2002) |
| neutrophil activating factor | <cytokine> A cytokine that activates neutrophils and attracts neutrophils and T-lymphocytes. It is released by several cell types including monocytes, macrophages, T-lymphocytes, fibroblasts, endothelial cells, and keratinocytes by an inflammatory stimulus. Il-8 is a member of the beta-thromboglobulin superfamily and structurally related to platelet factor 4. Acronym: IL-8 (12 Dec 1998) |
| insulin activating factor | <chemical> Activates insulin gene transcription in pancreatic beta cells. Synonym: insaf (05 Dec 1998) |
| osteoclast activating factor | A lymphokine that stimulates bone resorption and inhibits bone-collagen synthesis. (05 Mar 2000) |
| reverse transcription | <molecular biology> The process of copying information found in RNA into DNA. (09 Oct 1997) |
| transcription | <molecular biology> Synthesis of RNA by RNA polymerases using a DNA template. (18 Nov 1997) |
| transcription factors | Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process. (12 Dec 1998) |
| transcription factors, tfii | The so-called general transcription factors that bind to RNA polymerase II and that are required to initiate transcription. They include tfiia, tfiib, tfiid, tfiie, tfiif, tfiih, tfii-I, and tfiij. In vivo they apparently bind in an ordered multi-step process and/or may form a large preinitiation complex called RNA polymerase II holoenzyme. (12 Dec 1998) |
| transcription factors, tfiii | Factors that bind to RNA polymerase III and aid in transcription. They include the assembly factors tfiiia and tfiiic and the initiation factor tfiiib. All combine to form a preinitiation complex at the promotor that directs the binding of RNA polymerase III. (12 Dec 1998) |