Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Kinetic and equilibrium studies are presented for the reversible binding of [(3)H]dexamethasone by "specific" macromolecular receptors in the cytoplasmic fraction of cultured rat hepatoma cells. As in the case of the nuclear receptors in the same cells, the binding affinities of various steroids for the cytoplasmic receptors are closely correlated with the activities of these compounds as inducers of both tyrosine aminotransferase (EC 2.6.1.5) and cell adhesiveness. This suggests that the binding reaction is important for the biological effects of the hormones. Steroid-binding activity is inhibited by various proteases, mercurials, and 1 M KCl, but not by DNase or RNase. The receptors sediment in sucrose gradients in 0.5 M KCl near 4S, and at lower ionic strength near 7S; some of their physical properties are altered upon binding steroid. Bound dexamethasone can be recovered from the receptors as the unaltered steroid.
 ...
PMID:Specific cytoplasmic glucocorticoid hormone receptors in hepatoma tissue culture cells. 439 19

Fatty acid transport protein (FATP) was identified by expression cloning strategies (Schaffer, J. E., and Lodish, H. F. (1994) Cell 79, 427-436) and shown by transfection analysis to catalyze the transfer of long-chain fatty acids across the plasma membrane of cells. It is expressed highly in tissues exhibiting rapid fatty acid metabolism such as skeletal muscle, heart, and adipose. FATP mRNA levels are down-regulated by insulin in cultured 3T3-L1 adipocytes and up-regulated by nutrient depletion in murine adipose tissue (Man, M. Z., Hui, T. Y., Schaffer, J. E., Lodish, H. F., and Bernlohr, D. A. (1996) Mol. Endocrinol. 10, 1021-1028). To determine the molecular mechanism of insulin regulation of FATP transcription, we have isolated the murine FATP gene and its 5'-flanking sequences. The FATP gene spans approximately 16 kilobases and contains 13 exons, of which exon 2 is alternatively spliced. S1 nuclease and RNase protection assays revealed the presence of multiple transcription start sites; the DNA sequence upstream of the predominant transcription start sites lacks a typical TATA box. By transient transfection assays in 3T3-L1 adipocytes, the inhibitory action of insulin on FATP transcription was localized to a cis-acting element with the sequence 5'-TGTTTTC-3' from -1347 to -1353. This sequence is very similar to the insulin response sequence found in the regulatory region of other genes negatively regulated by insulin such as those encoding phosphoenolpyruvate carboxykinase, tyrosine aminotransferase, and insulin-like growth factor-binding protein 1. Fluorescence in situ hybridization analysis revealed that the murine FATP gene is localized to chromosome 8, band 8B3.3. Interestingly, this region of chromosome 8 contains a cluster of three other genes important for fatty acid homeostasis, lipoprotein lipase, the mitochondrial uncoupling protein 1 (UCP1) and sterol regulatory element-binding protein 1. These results characterize the murine FATP gene and its insulin responsiveness as well as present a framework for future studies of its role in lipid metabolism, obesity, and type II diabetes mellitus.
 ...
PMID:Characterization of the murine fatty acid transport protein gene and its insulin response sequence. 976 71

The insulin response element (IRE) in the IGFBP-1 promoter, and in other gene promoters, contains a T(A/G)TTT motif essential for insulin inhibition of transcription. Studies presented here test whether FKHR may be the transcription factor that confers insulin inhibition through this IRE motif. Immunoblots using antiserum to the synthetic peptide FKHR413-430, RNase protection, and Northerns blots show that FKHR is expressed in HEP G2 human hepatoma cells. Southwestern blots, electromobility shift assays, and DNase I protection assays show that Escherichia coli-expressed GST-FKHR binds specifically to IREs from the IGFBP-1, PEPCK and TAT genes; however, unlike HNF3beta, another protein proposed to be the insulin regulated factor, GST-FKHR does not bind the insulin unresponsive G/C-A/C mutation of the IGFBP-1 IRE. When HEP G2 cells were cotransfected with FKHR expression vectors and with IGFBP-1 promoter plasmids containing either native or mutant IREs, FKHR expression induced a 5-fold increase in activity of the native IGFBP-1 promoter but no increase in activity of promoter constructs containing insulin unresponsive IRE mutants. These data suggest that FKHR, and/or a related family member, is the important T(G/A)TTT binding protein that confers the inhibitory effect of insulin on gene transcription.
 ...
PMID:FKHR binds the insulin response element in the insulin-like growth factor binding protein-1 promoter. 1038 7

The expression and inducibility of four CYP2C genes, including CYP2C8, -2C9, -2C18, and -2C19, was investigated in primary cultures of human hepatocytes. By the use of RNase protection assay and specific antibodies, each CYP2C mRNA and protein were quantified unequivocally. The four CYP2C mRNAs were expressed in human livers and cultured primary hepatocytes, but only the CYP2C18 protein was not detected. Compounds known to activate the pregnane X receptor (PXR) such as rifampicin, or the constitutively activated receptor (CAR) such as phenobarbital, induced CYP2C8, CYP2C9, and to a lesser extent CYP2C19 mRNAs and proteins. CYP2C18 mRNA was expressed but not inducible. The concentration dependence of CYP2C8 and CYP2C9 mRNAs in response to rifampicin and phenobarbital paralleled that of CYP3A4 and CYP2B6, the maximum accumulation being reached with 10 microM rifampicin and 100 microM phenobarbital. In contrast, dexamethasone produced maximum induction of CYP2C8 and CYP2C9 mRNAs at 0.1 microM while in these conditions neither CYP3A4 nor CYP2B6 was significantly induced. Moreover, the concentration dependence of CYP2C8 and CYP2C9 mRNAs in response to dexamethasone paralleled that of tyrosine aminotransferase. Furthermore, dexamethasone, which has been recently shown to up-regulate PXR and CAR expression through the glucocorticoid receptor, potentiated CYP2C8 and CYP2C9 mRNA induction in response to rifampicin and phenobarbital. Collectively, these results suggest the possible implication of at least three receptors in the regulation of CYP2C8 and CYP2C9 expression, i.e., glucocorticoid receptor, PXR, and/or CAR.
 ...
PMID:Induction of CYP2C genes in human hepatocytes in primary culture. 1118 90

A ribonuclease, RNase T-tat, specifically designed to hydrolyze the TAR RNA of HIV-1 virus has been engineered. The protein was made by domain swapping the TAT peptide at the loop 3 position of ribonuclease T1. The RNase T-tat maintains a guanine-specific RNA hydrolytic activity, and characteristically displayed a specific affinity for the TAR RNA of HIV-1. In the in vitro and in vivo assays, the RNase T-tat preferentially inhibited the expression of TAR-bearing mRNA through cis-TAR targeting, suggesting that RNase T-tat may be potentially useful for the disruption of the initial stage of the transcription process of HIV-1 virus.
 ...
PMID:Creating a ribonuclease T-tat that preferentially recognizes and hydrolyzes HIV-1 TAR RNA in vitro and in vivo. 1808 2

The group II chaperonin thermosome (THS) is a hollow protein nanoparticle that can encapsulate macromolecular guests. Two large pores grant access to the interior of the protein cage. Poly(amidoamine) (PAMAM) is conjugated into THS to act as an anchor for small interfering RNA (siRNA), allowing to load the THS with therapeutic payload. THS-PAMAM protects siRNA from degradation by RNase A and traffics KIF11 and GAPDH siRNA into U87 cancer cells. By modification of the protein cage with the cell-penetrating peptide TAT, RNA interference is also induced in PC-3 cells. THS-PAMAM protein-polymer conjugates are therefore promising siRNA transfection reagents and greatly expand the scope of protein cages in drug delivery applications.
 ...
PMID:Chaperonin-Dendrimer Conjugates for siRNA Delivery. 2784 Jul 95

The major limitations with large and complex self-amplifying RNA vaccines (RepRNA) are RNase-sensitivity and inefficient translation in dendritic cells (DCs). Condensing RepRNA with polyethylenimine (PEI) gave positive in vitro readouts, but was largely inferior to virus-like replicon particles (VRP) or direct electroporation. In the present study, we improved such polyplex formulation and determined that fine-tuning of the polyplex structure is essential for ensuring efficacious translation. Thereby, three parameters dominate: (i) PEI molecular weight (MW); (ii) RepRNA:PEI (weight:weight) ratio; and (iii) inclusion of cell penetrating peptides (CPPs). Seven commercially available linear PEIs (MW 2,500-250,000) were classified as strong, intermediate or low for their aptitude at complexing and protecting RepRNA for delivery into porcine blood DCs. Inclusion of (Arg)9 or TAT(57-57) CPPs further modified the translation readouts, but varied for different gene expressions. Dependent on the formulation, translation of the gene of interest (GOI) inserted into the RepRNA (luciferase, or influenza virus hemagglutinin or nucleoprotein) could decrease, while the RepRNA structural gene (E2) translation increased. This was noted in the porcine SK6 cell line, as well as both porcine and, for the first time, human DCs. Two formulations - [Rep/PEI-4,000 (1:3)] and [Rep/PEI-40,000 (1:2)/(Arg)9] were efficacious in vivo in mice and pigs, where specific CD8+ T and CD4+ T-cell responses against the GOI-encoded antigen were observed for the first time. The results demonstrate that different polyplex formulations differ in their interaction with the RepRNA such that only certain genes can be translated. Thus, delivery of these large self-replicating RNA molecules require definition with respect to translation of different genes, rather than just the GOI as is the norm, for identifying optimal delivery for the desired immune activation in vivo.
 ...
PMID:Self-replicating RNA vaccine functionality modulated by fine-tuning of polyplex delivery vehicle structure. 2893 94