Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myristoyl-CoA:protein N-myristoyltransferase (NMT; EC 2.3.1.97) catalyzes the cotranslational linkage of myristate to the N-terminal glycine residues of several cellular, viral, and oncoproteins. We have recently synthesized a series of sulfur- and oxygen-substituted analogs of myristic acid that are similar in length to the 14:0 fatty acid yet have hydrophobicities equivalent to dodecanoate or decanoate. Previous in vitro enzyme assays and metabolic labeling studies indicate that some of these analogs are excellent substrates for NMT and are incorporated into subsets of cellular N-myristoyl proteins. Their sequence-specific incorporation probably arises from cooperative interactions between the acyl CoA and peptide binding sites of NMT. The human immunodeficiency virus 1 (HIV-1) and Moloney murine leukemia virus (MoMLV) depend on myristoylation of gag polyprotein precursors for assembly. We have tested four analogs--12-methoxydodecanoic acid, 10-propoxydecanoic acid, 5-octyloxypentanoic acid, and 11-ethylthioundecanoic acid--for their ability to block replication of these retroviruses. All reduce HIV-1 replication when incubated with CD4+ H9 cells for 10 days at 10-100 microM. 12-Methoxydodecanoic acid is most effective, producing a concentration-dependent decrease in (i) reverse transcriptase activity (to levels that were 5-10% of control at 20-40 microM), (ii) p24 levels, and (iii) syncytia formation. This degree of inhibition of HIV-1 replication is equivalent to that seen with 5 microM 3'-azido-3'-deoxythymidine and is accomplished without apparent toxicity, as measured by cell viability, protein, and nucleic acid synthesis. 5-Octyloxypentanoic acid inhibits MoMLV assembly in a dose-dependent fashion without accompanying cellular toxicity, while 12-methoxydodecanoic acid has no effect. These data suggest that the use of cellular NMT activity to deliver analogs of myristate with altered physical-chemical properties to proteins that undergo this cotranslational modification may represent an effective anti-viral therapeutic strategy as well as a way to investigate the role of covalently bound fatty acid in viral assembly.
...
PMID:Replication of human immunodeficiency virus 1 and Moloney murine leukemia virus is inhibited by different heteroatom-containing analogs of myristic acid. 281 17

We isolated a cDNA clone, kan-1, from a rat liver cDNA library using a reverse transcriptase PCR cloning method. The kan-1 cDNA encoded a polypeptide of 420 amino acids, and was 70 and 69% identical in nucleotide and amino acid sequences respectively with human liver bile acid-CoA-amino acid N-acyltransferase (BAT). Thus Kan-1 is probably a rat homologue of human BAT (rBAT). Kan-1/rBAT mRNA was mainly expressed in the livers of adult rats and rats immediately after, but not before, birth. It was expressed in the hepatocytes, the sinusoidal endothelial cells and the Kupffer cells of the liver. An anti-Kan-1/rBAT polyclonal antibody detected a protein of molecular mass 46 kDa in the liver. After partial hepatectomy, the levels of Kan-1/rBAT mRNA decreased at 6 and 12 h in the regenerating liver. In a sepsis model, hepatic expression of Kan-1/rBAT mRNA decreased at 6 and 12 h after caecal ligation and puncture. The kinetics of Kan-1/rBAT mRNA expression suggests that it may play a role in acute-phase reactions.
...
PMID:Reduced expression of kan-1 (encoding putative bile acid-CoA-amino acid N-acyltransferase) mRNA in livers of rats after partial hepatectomy and during sepsis. 757 55

In species such as the pig and human, gonadal steroidogenesis is believed to be dependent upon the availability of low density lipoprotein (LDL) cholesterol. However, before ovulation, Graafian follicles are impermeant to lipoproteins in the LDL class. Thus, de novo cholesterol biosynthesis via the rate-determining enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is likely to provide a significant mechanism for generating sterol substrate for steroidogenesis by granulosa cells before follicular rupture. As serum-free monolayer culture of (swine) granulosa cells offers an in vitro model of hormonally responsive HMG-CoA reductase, we generated a (porcine) complementary DNA and homologous complementary RNA to investigate by sensitive and specific ribonuclease protection assay the hormonal regulation of HMG-CoA reductase gene expression in ovarian cells from immature Graafian follicles. Using reverse transcriptase-polymerase chain reaction, we cloned and sequenced a 238-base pair complementary DNA from porcine luteal tissue that encodes the catalytic region of HMG-CoA reductase. GenBank analysis of the DNA sequence homology between the pig and other species showed the greatest concordance with human (88%) and hamster (90%). Solution hybridization/ribonuclease protection analysis of total RNA isolated from serum-free monolayer cultures of porcine granulosa cells revealed that insulin (3 micrograms/ml) increased HMG-CoA messenger RNA (mRNA) concentrations corrected for constitutive 18S ribosomal RNA expression in a time-dependent fashion, with significant effects observed at 12 h and a 6-fold increase by 48 h. Recombinant human insulin-like growth factor I (IGF-I) peptide was able to mimic the action of insulin alone. Neither FSH (100 ng/ml) nor 8-bromo-cAMP (1 mM) had observable effects on HMG-CoA message accumulation at any time point studied. However, the combined action of either FSH and insulin or 8-bromo-cAMP and insulin resulted in synergistic increases in reductase mRNA by 31- and 17-fold, respectively. To assess the possible feedback effects of sterol on HMG-CoA gene expression, granulosa cells were treated with LDL. At physiological concentrations, LDL suppressed basal expression of HMG-CoA mRNA to levels below the control value. In addition, LDL inhibited insulin-stimulated HMG-CoA mRNA accumulation by 84% as well as the synergistic effects of insulin and FSH (by 94%) and of insulin and 8-bromo-cAMP (by 93%). We conclude that insulin alone or in combination with FSH or cAMP augments the accumulation of HMG-CoA reductase mRNA in ovarian (granulosa) cells.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Regulation of porcine granulosa cell 3-hydroxy-3-methylglutaryl coenzyme A reductase by insulin and insulin-like growth factor I: synergism with follicle-stimulating hormone or protein kinase A agonist. 758 48

2,4-Dienoyl-CoA reductase (EC 1.3.1.34) participates in beta-oxidation of (poly)unsaturated enoyl-CoAs and it appears in mammalian mitochondria as two isoforms with molecular masses of 120 and 60 kDa [Hakkola and Hiltunen (1993) Eur. J. Biochem. 215, 199-204]. The 120 kDa isomer is a homotetrameric enzyme, and here we report cDNA cloning of its subunit from human. cDNA clones were isolated by reverse transcriptase-PCR from a fibrosarcoma cell line and by screening from a human liver lambda gt11 cDNA library. The 1128 bp clone contained an open reading frame of 1008 bp encoding a polypeptide of 335 amino acid residues with a predicted molecular mass of 36066 Da. This polypeptide represents the immature monomer of the 120 kDa enzyme, and it contains a predicted N-terminal mitochondrial targeting signal. The amino acid (nucleotide) sequence of human 2,4-dienoyl-CoA reductase shows 82.7% (81.7%) similarity (identity) to the corresponding sequence from the rat. Northern-blot analysis gave a single mRNA species of 1.2 kb in several human tissues, the amounts present in the tissues tested ranking as follows: heart approximately liver approximately pancreas > kidney >> skeletal muscle approximately lung. Immunoblotting of human and rat liver samples with an antibody to the subunit of the rat 120 kDa isoform indicates that the mature human enzyme is larger than its counterpart in the rat. The comparison of amino acid sequences for rat and human enzymes proposes that the difference in the size is 10 amino acid residues. The results show that the rat and human reductases are similar in many characteristics and that the reductase is expressed in human tissues capable of beta-oxidation of fatty acids.
...
PMID:Isolation and characterization of cDNA for human 120 kDa mitochondrial 2,4-dienoyl-coenzyme A reductase. 781 82

The present study exemplifies the method of quantitative reverse transcriptase-polymerase chain reaction (cRT-PCR) by quantifying, in bovine tissues, the specific mRNAs for the two key proteins which regulate cellular cholesterol metabolism, the low density lipoprotein (LDL)-receptor and the 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase. Our data reveal a broad range of expression for both mRNAs. The LDL-receptor mRNA expression was highest in the adrenal gland (6.7 x 10(4) molecules/micrograms cellular RNA) followed by the corpus luteum of the ovary, intermediate in the liver (8.6 x 10(2) molecules/micrograms cellular RNA) and not detectable in the large intestine. Expression of the HMG-CoA reductase almost paralleled LDL-receptor values. It was found to be highest in the ovary (6.1 x 10(6) molecules/micrograms cellular RNA) followed by the adrenal gland, intermediate in the liver (3.1 x 10(5) molecules/micrograms cellular RNA) and lowest in the large intestine (9.9 x 10(4) molecules/micrograms cellular RNA). These data are consistent with other reports concerning the quantitative analysis of the expression of both proteins as determined by other experimental approaches. Thus cRT-PCR is a valuable tool for the quantitative analysis of the LDL-receptor and the HMG-CoA reductase.
...
PMID:[Quantitative analysis of mRNA expression of the LDL receptor and HMG-CoA reductase in bovine tissue with competitive RT-PCR]. 797 94

We investigated the utility of noninvasive technology utilizing feces containing exfoliated colonocytes to determine whether changes in fecal fatty acid-binding proteins have predictive value in monitoring the neoplastic process. Ninety male Sprague-Dawley rats were randomly divided into four groups in a 2 x 2 factorial design, with two dietary fiber sources (wheat bran or oat bran) and two treatment groups (injection with a carcinogen, azoxymethane, or saline). Fresh fecal samples were collected at Week 16 postinjection, and tumor frequency was determined at Week 36 of the study. Semiquantitative "mimic" reverse transcriptase polymerase chain reaction was used to quantitate the expression of liver fatty acid-binding protein (L-FABP), intestinal fatty acid-binding protein (i-FABP), and acyl CoA-binding protein (ACBP) mRNA in fecal samples to establish their prognostic value. Rats fed wheat bran diets had a lower incidence of tumors (p < 0.05). There was no effect of carcinogen injection or tumor incidence on the expression of L-FABP, i-FABP, or ACBP mRNA, L-FABP and i-FABP mRNA expression were significantly higher (p < 0.05) in feces from animals fed a wheat bran diet than in feces from animals fed an oat bran diet. In contrast, the expression of ACBP mRNA was significantly lower (p < 0.05) in animals fed a wheat bran diet than in animals fed an oat bran diet. Wheat bran also increased (p < 0.05) the total excretion of L-FABP, i-FABP, and ACBP over a 48-hour period. These data suggest that exfoliated colonocyte fatty acid-binding protein mRNA status may provide insight into the mechanisms by which diet influences colonic physiology.
...
PMID:Dietary fiber differentially alters cellular fatty acid-binding protein expression in exfoliated colonocytes during tumor development. 991 20

Propionyl CoA carboxylase (PCC) is a mitochondrial, biotin-dependent enzyme involved in the catabolism of amino acids, odd-chain fatty acids, and other metabolites. PCC consists of two subunits, alpha and beta, encoded by the PCCA and PCCB genes, respectively. Inherited PCC deficiency due to mutations in either gene results in propionic acidemia (PA), an autosomal recessive disease. Surprisingly, PA is highly prevalent among Inuits in Greenland. We have analyzed reverse transcriptase-PCR products of the beta-subunit mRNA, to characterize the responsible mutation(s). A 3-bp insertion, 1540insCCC, was found in homozygous form in three patients and in compound heterozygous form in one patient. The resulting PCC has no measurable activity, and the mutant beta-subunit appears to be very unstable. To test the hypothesis that a common mutation is responsible for PA in the Greenlandic Inuit population, 310 anonymous DNA samples of Inuit origin were screened for 1540insCCC. We found a carrier frequency of 5%, which is very high compared with those of most other autosomal recessive diseases. Analysis of alleles of a very closely linked marker, D3S2453, revealed a high degree of linkage disequilibrium between one specific allele and 1540insCCC, suggesting that this mutation may be a founder mutation.
...
PMID:High incidence of propionic acidemia in greenland is due to a prevalent mutation, 1540insCCC, in the gene for the beta-subunit of propionyl CoA carboxylase. 1082 Jan 28

In the evolution of Type II diabetes, an initial period of hyper-fatty acidemia leads to an insulin secretory defect which triggers overt hyperglycemia and frank diabetes. The mechanism by which elevated free fatty acids contribute to beta-cell dysfunction, however, is not clearly understood. We recently reported that arachidonic acid (20:4) or linoleic acid (18:2) supplementations result in increases in abundances of long chain polyunsaturated fatty acids in INS-1 beta-cell membrane lipids, suggesting that beta-cells express desaturases that catalyze generation of unsaturated fatty acids. As expression of desaturases by beta-cells has not yet been addressed, we initiated studies to examine this issue using INS-1 beta-cells and find that they express messages for the Delta6-, stearoyl CoA-, and Delta5-desaturase. Supplementation of the INS-1 beta-cells with arachidonic acid leads to decreased expression of all three desaturases, presumably in response to the decreased need for endogenous generation of unsaturated fatty acids. In contrast, linoleic acid supplementation promoted minimal changes in the three desaturases. These findings demonstrate for the first time that beta-cells express regulatable desaturases. Additionally, reverse transcriptase-polymerase chain reaction analyses reveal expression of the desaturases in native pancreatic islets. It might be speculated that long-term elevations in fatty acids can also adversely influence desaturase activity in beta-cells and affect PUFA composition in beta-cell membranes contributing to beta-cell membrane structural abnormalities and altered secretory function.
...
PMID:Delta6-, Stearoyl CoA-, and Delta5-desaturase enzymes are expressed in beta-cells and are altered by increases in exogenous PUFA concentrations. 1192 99

The Avr9 peptide elicitor from the fungus Cladosporium fulvum, the bacterial pathogen Pseudomonas syringae pathovar tomato carrying the avirulence gene avrPto (Pst (avrPto)), and the organophosphorous insecticide fenitrothion induce resistance-related responses in tomato lines carrying the Cf-9, Pto, and Fen genes, respectively. These responses were associated with synthesis of p-coumaroyloctopamine and p-coumaroylnoradrenaline, a novel compound for plants. In susceptible near isogenic tomato lines (Cf-0, pto, fen) and wounded tomato leaves, the levels of these compounds were reduced or undetectable. The elevated levels of p-coumaroyloctopamine and p-coumaroylnoradrenaline were accompanied by elevated mRNA levels of genes encoding phenylalanine ammonia lyase, p-coumarate CoA ligase, and hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase (THT), enzymes that are involved in the hydroxycinnamic acid amide biosynthesis. Southern hybridization indicated that THT is encoded by a multigene family in tomato. Four different THT full-length cDNAs were derived by reverse transcriptase-PCR using degenerate primers based on potato and tobacco THT sequences. Transcripts for all four homologs were present in unchallenged tomato leaves, but only tomTHT1-3 was highly expressed following challenge with Pst (avrPto). Furthermore, tomTHT1-3 showed a more substantial and rapid induction in the incompatible interaction than in the compatible interaction. The cDNAs tomTHT1-3, tomTHT7-1, and tomTHT7-8 encoded proteins with a high degree of amino acid sequence homology, although the recombinant proteins had different preferences for octopamine and noradrenaline. The fourth cDNA, tomTHT1-4, directed synthesis of a truncated enzymatically inactive protein due to the presence of a premature stop codon.
...
PMID:p-Coumaroylnoradrenaline, a novel plant metabolite implicated in tomato defense against pathogens. 1290 Apr 12

A polyketide synthase has been suggested to play an important role in cannabinoid biosynthesis in Cannabis sativa L. This enzyme catalyzes the biosynthesis of olivetolic acid, one of the precursors for cannabinoid biosynthesis. Using a reverse transcriptase-polymerase chain reaction (RT-PCR) based on the DNA homology of chalcone synthase (EC 2.3.1.156) and valerophenone synthase (EC 2.3.1.156) of hop (Humulus lupulus), a cDNA encoding a polyketide synthase in C. sativa was identified. The coding region of the gene is 1170 bp long encoding a 389 amino acid protein of a predicted 42.7 kDa molecular mass and with a pI of 6.04. The gene shares a high homology with a chalcone synthase gene of H. lupulus, 85% and 94% homology on the level of DNA and protein, respectively. Over-expression of the construct in Escherichia coli M15 resulted in a 45 kDa protein. The protein has chalcone synthase activity as well as valerophenone synthase activity, a chalcone synthase-like activity. Using n-hexanoyl-CoA and malonyl-CoA as substrates did not give olivetol or olivetolic acid as a product.
...
PMID:Cloning and over-expression of a cDNA encoding a polyketide synthase from Cannabis sativa. 1512 Jan 13


1 2 Next >>

---