Search results for "Specificity."
showing 10 items of 2232 documents
Expression analysis and functional activity of interleukin-7 splice variants.
2008
Alternative splicing results in multiple protein isoforms derived from a single gene. The magnitude of this process ranges from a complete loss of function to gain of new function. We examined, as a paradigm, alternative splicing of the non-redundant human cytokine, interleukin-7 (IL-7). We show that extensive IL-7 splicing in human tissues of different histology, including MTB+ granuloma lesions, transformed tissue and tumor cell lines. IL-7 splice variants were expressed as recombinant proteins. A differentially spliced IL-7 isoform, lacking exon 5, leads to STAT-5 phosphorylation in CD4+ and CD8+ T cells, promotes thymocyte maturation and T-cell survival. Human tumor lesions show aberran…
Quantitative RT-PCR measurement of human cytochrome P-450s: application to drug induction studies.
2000
A quantitative RT-PCR assay has been developed that is able to measure the mRNA content of the major human CYPs (1A1, 1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1, 3A4, and 3A5). The technique is highly specific, reproducible, rapid, and sensitive enough to quantitate low and high abundant mRNAs. The PCR primers were selected to specifically match each CYP mRNA, to have a very close annealing temperature, and to render PCR products of similar sizes. The PCR conditions were designed to allow the simultaneous measurement of the various human liver CYPs in a single run. To achieve precise and reproducible quantitation of each cytochrome mRNA, a external standard (luciferase mRNA) is added to the probes …
A new metallothionein gene from the giant keyhole limpet Megathura crenulata.
2003
Abstract Metallothioneins (MTs) are small soluble proteins ubiquitously expressed in animals and plants. Different isoforms are present in deuterostomes and protostomes. They do not differ greatly in primary structure, but are clearly distinguishable. Here, I present the gene and the complete cDNA of a novel MT from the mollusk Megathura crenulata . This protein is closely related to the Cu-inducible MTs of the vineyard snail Helix pomatia , but has also some minor sequence features typical of Cd-inducible isoforms of H . pomatia and other molluscs. Overall, the deduced primary structure is similar to the known molluscan MTs, but in addition possesses an insertion of 5 amino acids not found…
2′,5′-oligoadenylate synthetase from a lower invertebrate, the marine sponge Geodia cydonium, does not need dsRNA for its enzymatic activity
2002
AbstractRecently, the presence of 2′,5′-linked oligoadenylates and a high 2′,5′-oligoadenylate synthetase activity were discovered in a lower invertebrate, the marine sponge Geodia cydonium. It has been demonstrated that mammalian 2–5A synthetase isozymes require a dsRNA cofactor for their enzymatic activity. Our results show that, unlike mammalian 2–5A synthetases, the 2–5A synthetase from the sponge acts in a dsRNA-independent manner in vitro. A prolonged incubation of the G. cydonium extract with a high concentration of a micrococcal nuclease had no effect on the activity of the 2–5A synthetase. At the same time, the micrococcal nuclease was effective within 30 min in degrading dsRNA nee…
The diversity of GABAA receptors. Pharmacological and electrophysiological properties of GABAA channel subtypes.
1998
The amino acid gamma-aminobutyric-acid (GABA) prevails in the CNS as an inhibitory neurotransmitter that mediates most of its effects through fast GABA-gated Cl(-)-channels (GABAAR). Molecular biology uncovered the complex subunit architecture of this receptor channel, in which a pentameric assembly derived from five of at least 17 mammalian subunits, grouped in the six classes alpha, beta, gamma, delta, sigma and epsilon, permits a vast number of putative receptor isoforms. The subunit composition of a particular receptor determines the specific effects of allosterical modulators of the GABAARs like benzodiazepines (BZs), barbiturates, steroids, some convulsants, polyvalent cations, and et…
Efficient Expression and Crystallization System of Cancer-Associated Carbonic Anhydrase Isoform IX.
2015
Human carbonic anhydrase IX (CA IX) is overexpressed in a number of solid tumors and is considered to be a marker for cellular hypoxia that it is not produced in most normal tissues. CA IX contributes to the acidification of the extracellular matrix, which, in turn, favors tumor growth and metastasis. Therefore, CA IX is considered to be a promising anti-cancer drug target. However, the ability to specifically target CA IX is challenging due to the fact that the human genome encodes 15 different carbonic anhydrase isoforms that have a high degree of homology. Furthermore, structure-based drug design of CA IX inhibitors so far has been largely unsuccessful due to technical difficulties regar…
The Xenopus Oocyte as an Ectopic Expression System for the Selection of Protein Isoform-Specific Antibodies
1993
A panel of Xenopus oocytes, each injected with cRNA coding for one specific isoform of the rat brain RCK family of voltage gated potassium channel proteins, was employed to screen for isoform-specific monoclonal antibodies. Several days after injection, cryosections of embedded oocytes were produced and were employed in immunohistochemical analysis of antibody binding. Of the advantageous properties of the assay, it employs the native antigen, it can be applied to homooligomeric and heterooligomeric proteins, and cryosections of the same batch can be stored frozen for later tests. The method may be advantageous also for the selection of isoform-specific antibodies of other protein families.
Application of an ectopic expression system for the selection of protein-isoform-specific antibodies. The monoclonal antibody K1 C3 is specific for t…
1993
Monoclonal antibodies were raised against a fusion protein consisting of a fragment of 141 amino acids of the C-terminal region of the rat brain voltage-gated K(+)-channel protein (RCK1) and the lambda N protein (fusion protein I). Selection of K(+)-channel-specific hybridoma cell lines was performed by means of an ELISA employing a fusion protein consisting of the K(+)-channel-specific peptide sequence and glutathione S-transferase (fusion protein II). For final selection of RCK1 isoform-specific antibodies, a panel of Xenopus oocytes was employed, each injected with cRNA coding for a specific RCK isoform (RCK 1, 2, 4 or 5). Several days after injection, cryosections of embedded oocytes we…
Tissue- and cell-specific expression of metallothionein genes in cadmium- and copper-exposed mussels analyzed by in situ hybridization and RT–PCR
2007
Abstract Metallothioneins (MTs) are metal-inducible proteins that can be used as biomarkers of metal exposure. In mussels two families of MT isoforms (MT10 and MT20) have been characterized. In this study, mussels (Mytilus galloprovincialis) were exposed to 200 ppb Cd and 40 ppb Cu for 2 and 9 days to characterize the tissue and isoform specificity of metal-induced MT expression. Non-radioactive in situ hybridization demonstrated that both MT isoforms were mainly transcribed in digestive tubule epithelial cells, especially in basophilic cells. Weaker MT expression was detected in non-ciliated duct cells, stomach and gill epithelial cells, haemocytes, adipogranular cells, spermatic follicles…
Midgut aminopeptidase N isoforms from Ostrinia nubilalis: Activity characterization and differential binding to Cry1Ab and Cry1Fa proteins from Bacil…
2013
Aminopeptidase N (APN) isoforms from Lepidoptera are known for their involvement in the mode of action of insecticidal Cry proteins from Bacillus thuringiensis. These enzymes belong to a protein family with at least eight different members that are expressed simultaneously in the midgut of lepidopteran larvae. Here, we focus on the characterization of the APNs from Ostrinia nubilalis (OnAPNs) to identify potential Cry receptors. We expressed OnAPNs in insect cells using a baculovirus system and analyzed their enzymatic activity by probing substrate specificity and inhibitor susceptibility. The interaction with Cry1Ab and Cry1Fa proteins (both found in transgenic insect-resistant maize) was …