Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary astroglial cultures were incubated with delta (10(-6) M DPDPE) or kappa (10(-5) M U-50,488H) receptor agonists for 5 days. Thereafter, the acute inhibitory actions of delta or kappa receptor agonists on forskolin stimulated cAMP accumulation were assayed. The G alpha s, G alpha i-1 and G alpha i-2 mRNA levels were quantified after 5 days of either delta or kappa receptor agonist treatment using a solution hybridization, RNase protection assay. Pronounced effects were observed after 5 days of kappa receptor agonist [10(-5) M U-50,488H] incubation. This treatment resulted in an attenuation in the acute inhibitory action of delta and kappa receptor agonists. Furthermore, a decreased stimulatory action of forskolin was seen. Similar effects were also seen after delta receptor stimulation. We also investigated the effects after 24 h and 3 days of incubation with the kappa receptor agonist (10(-5) M) U-50,488H. The 24 h incubation resulted in a decreased sensitivity to the acute inhibitory action of delta and kappa receptor agonists in the astroglial cultures. This effect was further accentuated after the 3 days of incubation with 10(-5) M U-50,488H. No significant change was seen in the basal accumulation of cAMP after incubation with the kappa agonist U-50,488H. However, after 5 days of incubation with the delta agonist DPDPE, a significantly increased basal accumulation of cAMP was seen in the astroglial cultures. After 5 days of delta or kappa agonist incubation, an increase in G alpha s mRNA level and a decrease in G alpha i-2 mRNA level was seen compared with controls. No statistically significant alterations in the amount of G alpha i-1 mRNA were seen. The data obtained in the present study indicate that the effects of long-term opioid treatment alters the sensitivity of glial cell opioid receptors. Furthermore, long term opioid treatment induces alterations in glial G-protein mRNA levels.
Brain Res Mol Brain Res 1992 Dec
PMID:Regulation of G-PROTEIN mRNA abundancy and cAMP accumulation after long-term opioid incubation in primary cultures of astroglia from the rat cerebral cortex. 133 44

We searched for somatic mutations of the adenomatous polyposis coli (APC) gene in DNA samples isolated from 57 sporadic gastric cancers, by means of a ribonuclease (RNase) protection analysis coupled with DNA amplification by the polymerase chain reaction (PCR). Examining 30% of the APC coding region, including a region where somatic mutations in colorectal tumors are known to be clustered, we detected somatic mutations in 12 tumors; seven in 17 very well differentiated adenocarcinomas, two in 19 well or moderately differentiated adenocarcinomas, and three in ten signet-ring cell carcinomas. So far, no somatic mutations have been identified in 11 poorly differentiated adenocarcinomas. Eight of the 17 somatic mutations found in 12 tumors caused truncation of the gene product due to a nonsense mutation and a 1-, 2- or 5-bp deletion; nine others were point mutations that altered amino acids. Our results suggest that inactivation of APC plays a role in development of some gastric cancers, particularly very well differentiated adenocarcinomas and signet-ring cell carcinomas.
Hum Mol Genet 1992 Nov
PMID:Somatic mutation of the APC gene in gastric cancer: frequent mutations in very well differentiated adenocarcinoma and signet-ring cell carcinoma. 133 91

A defective S-allele, S(o), and a functional S-allele, Sx, have previously been found to be retained in an F1 hybrid of a self-compatible commercial cultivar of Petunia hybrida. Pistil proteins associated with these two alleles have also been identified. Their amino-terminal sequences have been found to share a high degree of similarity with those of S-proteins characterized from self-incompatible solanaceous species. Here we report the isolation and sequencing of cDNAs encoding S(o)- and Sx-proteins. Their deduced amino acid sequences contain all the consensus primary structural features of S-proteins from self-incompatible solanaceous species. Both proteins also have ribonuclease activity. The implications of these findings are discussed in relation to the presumed function of the S-protein in the self-incompatibility interaction.
Plant Mol Biol 1992 Jun
PMID:Cloning and sequencing of cDNAs encoding two S proteins of a self-compatible cultivar of Petunia hybrida. 134 83

On the basis of molecular dynamics and free-energy perturbation approaches, the Glu46Gln (E46Q) mutation in the guanine-specific ribonuclease T1 (RNase T1) was predicted to render the enzyme specific for adenine. The E46Q mutant was genetically engineered and characterized biochemically and crystallographically by investigating the structures of its two complexes with 2'AMP and 2'GMP. The ribonuclease E46Q mutant is nearly inactive towards dinucleoside phosphate substrates but shows 17% residual activity towards RNA. It binds 2'AMP and 2'GMP equally well with dissociation constants of 49 microM and 37 microM, in contrast to the wild-type enzyme, which strongly discriminates between these two nucleotides, yielding dissociation constants of 36 microM and 0.6 microM. These data suggest that the E46Q mutant binds the nucleotides not to the specific recognition site but to the subsite at His92. This was confirmed by the crystal structures, which also showed that the Gln46 amide is hydrogen bonded to the Phe100 N and O atoms, and tightly anchored in this position. This interaction may either have locked the guanine recognition site so that 2'AMP and 2'GMP are unable to insert, or the contribution to guanine recognition of Glu46 is so important that the E46Q mutant is unable to function in recognition of either guanine and adenine.
J Mol Biol 1992 May 20
PMID:RNase T1 mutant Glu46Gln binds the inhibitors 2'GMP and 2'AMP at the 3' subsite. 135 Jun 42

We have investigated the ability of dehydroepiandrosterone (DHEA) to alter the production of interleukin-2 (IL-2) and to bind to a specific binding complex in antiCD3 epsilon activated T cells. Binding activity correlated with the presence of a specific DHEA binding complex in the cytosol and nuclei of DHEA-responsive T-cell hybridomas, as well as in CD4+ and CD8+ cells isolated from peripheral lymph nodes of normal mice. Scatchard analysis determined that intact lymphocytes and cytosolic fractions contained high affinity binding for [3H]DHEA (approx. 2.6 nM) with 1000-7000 binding sites existing per cell. Five of the T-cell hybridomas tested both responded to DHEA treatment with increased production of IL-2 and also contained specific high affinity [3H]DHEA binding. Four additional T-cell hybridomas were found to contain no specific [3H]DHEA binding and were also unresponsive to DHEA influences on IL-2 production. Sucrose density gradients demonstrated a 3-4s [3H]DHEA binding complex in high salt and a 7-8s binding complex in low salt. Specific binding was inhibited by preincubation of the cytosol fractions with either trypsin or chymotrypsin, or by heating to 60 degrees C for 1 h (less than 15% of control). [3H]DHEA binding was unaffected by preincubation of the cytosol fractions with ribonuclease, deoxyribonuclease, or phospholipase A. The DHEA-protein complexes bound to DNA-cellulose with the amount of binding being slightly increased by preincubation at 25 degrees C as compared to 4 degrees C. As expected, [3H]DHEA binding was inhibited by the addition of unlabeled DHEA, but was also modestly inhibited by dihydrotestosterone and cortisol. Binding of DHEA was unaffected by progesterone, dexamethasone, estradiol, androsterone, DHEAS, and beta-etiocholanolone at all concentrations tested. DHEA was incapable of inhibiting the binding of [3H]DHT to the androgen receptor or [3H]dexamethasone to the glucocorticoid receptor. Collectively, these findings suggest that murine T cells contain a specific DHEA receptor. We believe that DHEA is a steroid hormone that is directly involved in the regulation of IL-2 production by both normal and some T-cell hybridomas.
J Steroid Biochem Mol Biol 1992 May
PMID:The presence of a dehydroepiandrosterone-specific receptor binding complex in murine T cells. 135 1

Messenger RNA encoding a protein kinase closely related to the catalytic subunit of skeletal muscle phosphorylase kinase has previously been isolated from a human HeLa cell cDNA library, and cross-species Northern hybridization analysis has shown that the rat homolog of this transcript is abundant in the adult testis (Hanks, S.K. (1989) Mol. Endocrinol. 3, 110-116). We now propose that the protein encoded by this transcript be designated as "PhK-gamma T." In this article, the primary structure of the rat homolog of PhK-gamma T is described, as deduced from nucleotide sequences of cDNA and genomic clones. RNase protection analysis reveals that PhK-gamma T transcripts are actually present in a wide variety of adult rat tissues, but at levels 20-100-fold less than what is observed in the testis. In the testis, transcription of the PhK-gamma T gene is initiated at multiple sites as shown by RNase protection and primer extension. Enzymatic activity of PhK-gamma T was demonstrated using renatured bacterially expressed protein. In the presence of Ca2+/calmodulin, PhK-gamma T is able to efficiently phosphorylate glycogen phosphorylase and convert it from an inactive to an active form. We conclude that PhK-gamma T represents a true isoform of phosphorylase kinase catalytic subunit.
 ...
PMID:Molecular cloning and enzymatic analysis of the rat homolog of "PhK-gamma T," an isoform of phosphorylase kinase catalytic subunit. 137 Apr 75

Molecular hybridisation using a ricin cDNA probe has revealed that the ricin/Ricinus communis agglutinin (RCA) multigene family is composed of approximately eight members. Several genomic clones containing preproricin and preproricin-like sequences have been isolated. Partial analysis of three different genomic clones by DNA sequencing and ribonuclease protection has indicated that at least three members of the lectin gene family are non-functional. None of the original seventeen positive clones isolated appears to contain a Ricinus communis agglutinin (RCA) gene. One gene member analysed (pCBG3H1) represents a functional ricin gene similar in coding sequence to the published cDNA sequence and possesses typical eukaryotic consensus sequences and seed-specific elements within the flanking sequences. Investigation at the transcriptional level of the expression pattern of this gene revealed that mRNA accumulates during the post-testa stages of seed development. The pattern of accumulation of steady-state transcripts correlates closely with that previously observed at the protein and translatable RNA levels.
Plant Mol Biol 1992 Feb
PMID:The lectin gene family of Ricinus communis: cloning of a functional ricin gene and three lectin pseudogenes. 137 5

Phosphorothioate oligodeoxycytidine (S-dCn) was used as a model compound to examine the impact of the number of phosphorothioate linkages and their position on the inhibition of human DNA polymerases and RNase H in vitro. S-dCn with a chain length longer than 15 could inhibit human DNA polymerases and RNase H activities, in a linkage number-dependent manner. Longer oligomers were more potent inhibitors than shorter ones. Kinetic studies indicated that S-dC28 was a competitive inhibitor of DNA polymerase alpha and beta with respect to the DNA template, whereas it was a noncompetitive inhibitor of polymerases gamma and delta. S-dC28 was also a competitive inhibitor of RNase H1 and H2 with respect to RNA-DNA duplex. Susceptibility of these enzymes to inhibition by S-dC28 was in the order of delta approximately gamma greater than alpha greater than beta and RNase H1 greater than RNase H2. Structural-activity relationships were explored with a group of S-dC28 analogs that have phosphorothioate internucleotide linkages at various positions. The inhibitory effect depended on the total number of thioate linkages, rather than the position of the linkages within the oligomer or the chain length itself. No sequence specificity was found. In the presence of the complementary RNA, antisense phosphorothioates (S-oligos) exerted a biphasic effect on RNase H activity. At low concentrations S-oligos could enhance the cleavage of the RNA portion of S-oligo-RNA duplex, whereas at high concentrations (in excess of the complementary RNA) S-oligos could inhibit RNase H and protect the complementary RNA from degradation. Together, these results suggest that the non-sequence-specific inhibitory effect of S-oligos should be taken into consideration in designing antisense inhibitors. This inhibitory activity could be avoided by decreasing the number of phosphorothioate linkages at the backbone, and S-oligos of 15-20 residues are preferable in antisense molecule design.
Mol Pharmacol 1992 Feb
PMID:Phosphorothioate oligonucleotides are inhibitors of human DNA polymerases and RNase H: implications for antisense technology. 137 82

Insulin-like growth factors I and II (IGF I and II) are polypeptides with both growth-promoting and insulin-like metabolic effects. Immunoreactive IGF I is present in the retina and both IGF I and II are present in vitreal fluid. The type I and type II IGF receptors are also localized within the neural retina. The presence of IGFs and IGF receptors within the eye suggests a possible growth-promoting effect of IGFs on ocular tissues. IGF may enter the eye from the blood or, alternatively, arise from an ocular cell type which synthesizes and secretes IGF. IGF I and II mRNA synthesis in scleral cells and IGF I synthesis in rat retina suggests endogenous IGF production in the eye. We hypothesized that IGFs and IGF receptors are synthesized by one ocular cell type, the retinal pigment-epithelium (RPE). As a first step in studying IGF production by the RPE, we analyzed expression of the IGF and IGF receptor genes by cultured human RPE cells. Using Northern analysis, RNase protection and reverse-transcriptase polymerase chain reaction (RT-PCR), we found that cultured RPE cells synthesize mRNA for IGF I and the type I and type II IGF receptors.
Brain Res Mol Brain Res 1992 Jan
PMID:Gene expression of the insulin-like growth factors and their receptors in cultured human retinal pigment epithelial cells. 137 66

The human Fc gamma receptor gene Fc gamma RIIA is expressed in platelets, neutrophils, monocytes and macrophages. Understanding the regulation of expression of Fc gamma RIIA will enhance our knowledge of regulated gene expression and immune function in these cells. We cloned a 3.65 kb region of the 5' end of the Fc gamma RIIA gene and characterized 3.4 kb of previously unreported sequence of the 5'-flanking region. Primer extension studies and RNase protection analyses of mRNA from HEL, K562 and U937 cells revealed multiple transcription start sites. One transcription start site mapped to a 5'-untranslated (5'UT) exon approximately 1 kb 5' to the ATG translation initiation codon, while a second start site mapped near the ATG codon. Reverse transcription combined with PCR (RT-PCR) employing an oligonucleotide in the putative 5'UT exon and an antisense oligonucleotide in the translated region yielded products which confirm that transcription starts in this 5'UT exon 881 bp upstream of the ATG codon. Sequence analysis of the RT-PCR products showed two related RNA splice products which use alternative 3'-consensus AG splice acceptor sites. Fc gamma RIIA mRNA thus has three distinct potential 5'UT regions, two alternatively spliced forms from the start site in the 5'UT exon and the third from the start site near the ATG codon. Comparisons of the human Fc gamma RIIA 5'-flanking region with human Fc gamma RI and mouse Fc gamma RII beta genes as well as with other genes expressed in megakaryocytes, neutrophils and monocytes reveal structural similarities and shared promoter elements.
Mol Immunol 1992 Oct
PMID:Characterization of the 5'-flanking transcriptional regulatory region of the human Fc gamma receptor gene, Fc gamma RIIA. 138 18


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>