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An exon is any part of a gene that will encode a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term exon refers to both the DNA sequence within a gene and to the corresponding sequence in RNA transcripts. In RNA splicing, introns are removed and exons are covalently joined to one another as part of generating the mature messenger RNA. Just as the entire set of genes for a species constitutes the genome, the entire set of exons constitutes the exome.
African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic infection of humans and other animals. It is caused by the species Trypanosoma brucei. Humans are infected by two types, Trypanosoma brucei gambiense (TbG) and Trypanosoma brucei rhodesiense (TbR). TbG causes over 98% of reported cases. Both are usually transmitted by the bite of an infected tsetse fly and are most common in rural areas.
Trypanosomatida is a group of kinetoplastid excavates distinguished by having only a single flagellum. The name is derived from the Greek trypano (borer) and soma (body) because of the corkscrew-like motion of some trypanosomatid species. All members are exclusively parasitic, found primarily in insects. A few genera have life-cycles involving a secondary host, which may be a vertebrate, invertebrate or plant. These include several species that cause major diseases in humans. Trypanosomatida are intracellular parasites.
Tsetse, sometimes spelled tzetze and also known as tik-tik flies, are large biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus Glossina, which are placed in their own family, Glossinidae. The tsetse are obligate parasites that live by feeding on the blood of vertebrate animals. Tsetse have been extensively studied because of their role in transmitting disease. They have a prominent economic impact in sub-Saharan Africa as the biological vectors of trypanosomes, which cause human sleeping sickness and animal trypanosomiasis. Tsetse are multivoltine and long-lived, typically producing about four broods per year, and up to 31 broods over their lifespans.
Glycosylphosphatidylinositol, or glycophosphatidylinositol, or GPI in short, is a phosphoglyceride that can be attached to the C-terminus of a protein during posttranslational modification. The resulting GPI-anchored proteins play key roles in a wide variety of biological processes. GPI is composed of a phosphatidylinositol group linked through a carbohydrate-containing linker and via an ethanolamine phosphate (EtNP) bridge to the C-terminal amino acid of a mature protein. The two fatty acids within the hydrophobic phosphatidyl-inositol group anchor the protein to the cell membrane.
Trypanosoma is a genus of kinetoplastids, a monophyletic group of unicellular parasitic flagellate protozoa. Trypanosoma is part of the phylum Sarcomastigophora. The name is derived from the Greek trypano- (borer) and soma (body) because of their corkscrew-like motion. Most trypanosomes are heteroxenous and most are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. Some, such as Trypanosoma equiperdum, are spread by direct contact. In an invertebrate host they are generally found in the intestine, but normally occupy the bloodstream or an intracellular environment in the vertebrate host.
PARP may refer to:
The low-density lipoprotein (LDL) receptor (LDL-R) is a mosaic protein of 839 amino acids that mediates the endocytosis of cholesterol-rich LDL. It is a cell-surface receptor that recognizes the apoprotein B100, which is embedded in the outer phospholipid layer of LDL particles. The receptor also recognizes the apoE protein found in chylomicron remnants and VLDL remnants (IDL). In humans, the LDL receptor protein is encoded by the LDLR gene on chromosome 19. It belongs to the low density lipoprotein receptor gene family. It is most significantly expressed in bronchial epithelial cells and adrenal gland and cortex tissue.
Trypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma. This parasite is the cause of vector-borne diseases of vertebrate animals, including humans, carried by species of tsetse fly in sub-Saharan Africa. In humans T. brucei causes African trypanosomiasis, or sleeping sickness. In animals it causes animal trypanosomiasis, also called nagana in cattle and horses. T. brucei has traditionally been grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense. The first is a parasite of non-human vertebrates, while the latter two are known to be parasites of humans. Only rarely can the T. b. brucei infect a human.
Trypanosoma evansi is a species of excavate trypanosome in the genus Trypanosoma that causes one form of surra in animals. It has been proposed that T. evansi is—like T. equiperdum—a derivative of T. brucei. Due to this loss of part of the mitochondrial (kinetoplast) DNA T. evansi is not capable of infecting the invertebrate vector and establishing the subsequent life-stages. Due to its mechanical transmission T. evansi is not restricted to transmission via the tsetse fly but shows a very broad vector specificity including the genera Tabanus, Stomoxys, Haematopota, Chrysops and Lyperosia. It rarely causes disease in humans, indeed, it has only been recorded in cases where the patient lacks a normal component of human serum, Apolipoprotein L1. T. evansi is very common in India and Iran and causes acute disease in camels and horses, and chronic disease in cattle and buffalo. In Pakistan, it has been found to be the most prevalent trypanosome species in donkeys.
Subtelomeres are segments of DNA between telomeric caps and chromatin.
Antigenic variation or antigenic alteration refers to the mechanism by which an infectious agent such as a protozoan, bacterium or virus alters the proteins or carbohydrates on its surface and thus avoids a host immune response, making it one of the mechanisms of antigenic escape. It is related to phase variation. Antigenic variation not only enables the pathogen to avoid the immune response in its current host, but also allows re-infection of previously infected hosts. Immunity to re-infection is based on recognition of the antigens carried by the pathogen, which are "remembered" by the acquired immune response. If the pathogen's dominant antigen can be altered, the pathogen can then evade the host's acquired immune system. Antigenic variation can occur by altering a variety of surface molecules including proteins and carbohydrates. Antigenic variation can result from gene conversion, site-specific DNA inversions, hypermutation, or recombination of sequence cassettes. The result is that even a clonal population of pathogens expresses a heterogeneous phenotype. Many of the proteins known to show antigenic or phase variation are related to virulence.
The translationally controlled tumour protein, commonly known as TCTP, is a highly conserved protein among many eukaryotic organisms. TCTP is involved in a variety of cellular activities, including microtubule stabilization, calcium-binding activities, and apoptosis. The Mammalian translationally controlled tumour protein (TCTP) is a protein which has been found to be preferentially synthesised in cells during the early growth phase of some types of tumour, but which is also expressed in normal cells. It was first identified as a histamine-releasing factor, acting in IgE +-dependent allergic reactions. In addition, TCTP has been shown to bind to tubulin in the cytoskeleton, has a high affinity for calcium, is the binding target for the antimalarial compound artemisinin, and is induced in vitamin D-dependent apoptosis. TCTP production is thought to be controlled at the translational as well as the transcriptional level.
4F2 cell-surface antigen heavy chain is a protein that in humans is encoded by the SLC3A2 gene.
Haptoglobin-related protein is a protein that in humans is encoded by the HPR gene. The HPR gene affects hereditary immunity to a non-pathogenic species of African trypanosomes.
The B recognition element (BRE) is a DNA sequence found in the promoter region of most genes in eukaryotes and Archaea. The BRE is a cis-regulatory element that is found immediately near TATA box, and consists of 7 nucleotides. There are two sets of BREs: one (BREu) found immediately upstream of the TATA box, with the consensus SSRCGCC; the other (BREd) found around 7 nucleotides downstream, with the consensus RTDKKKK.
Coat protein may refer to:
Wendy Gibson is Professor of Protozoology at University of Bristol, specialising in tyrpanosomes and molecular parasitology.
Variant surface glycoprotein (VSG) is a ~60kDa protein which densely packs the cell surface of protozoan parasites belonging to the genus Trypanosoma. This genus is notable for their cell surface proteins. They were first isolated from Trypanosoma brucei in 1975 by George Cross. VSG allows the trypanosomatid parasites to evade the mammalian host's immune system by extensive antigenic variation. They form a 12–15 nm surface coat. VSG dimers, ~90% of all cell surface protein. It also makes up ~10% of total cell protein. For this reason, these proteins are highly immunogenic and an immune response raised against a specific VSG coat will rapidly kill trypanosomes expressing this variant. However, with each cell division there is a possibility that the progeny will switch expression to change the VSG that is being expressed. VSG has no prescribed biochemical activity.
Piet Borst is emeritus professor of Clinical Biochemistry and Molecular Biology at the University of Amsterdam (UVA), and until 1999 Director of Research and Chairman of the Board of Directors of the Netherlands Cancer Institute and the Antoni van Leeuwenhoekziekenhuis (NKI-AVL). He continued to work at the NKI-AVL as a staff member and group leader until 2016.
References
- ↑ Rudenko G, Le Blancq S, Smith J, Lee MG, Rattray A, Van der Ploeg LH (July 1990). "Procyclic acidic repetitive protein (PARP) genes located in an unusually small alpha-amanitin-resistant transcription unit: PARP promoter activity assayed by transient DNA transfection of Trypanosoma brucei". Mol. Cell. Biol. 10 (7): 3492–504. doi:10.1128/MCB.10.7.3492. PMC 360784 . PMID 1694012.
- ↑ Acosta-Serrano A, Vassella E, Liniger M, Kunz Renggli C, Brun R, Roditi I, Englund PT (February 2001). "The surface coat of procyclic Trypanosoma brucei: programmed expression and proteolytic cleavage of procyclin in the tsetse fly". Proc. Natl. Acad. Sci. U.S.A. 98 (4): 1513–8. Bibcode:2001PNAS...98.1513A. doi: 10.1073/pnas.98.4.1513 . PMC 29288 . PMID 11171982.
- ↑ Bütikofer P, Ruepp S, Boschung M, Roditi I (September 1997). "'GPEET' procyclin is the major surface protein of procyclic culture forms of Trypanosoma brucei brucei strain 427". Biochem. J. 326 (2): 415–23. doi:10.1042/bj3260415. PMC 1218686 . PMID 9291113.
