Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039483 (giant cell arteritis)
 3,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The (+)-trans-anti-benzo[a]pyrene adduct formed at the N2 amino group of guanine is the major adduct found after metabolic activation of the ubiquitous carcinogen benzo[a]pyrene. The carcinogenic and mutagenic properties of the (+)-trans-anti-BP adduct, as well as related adducts, have been extensively studied. A DNA duplex containing a (+)-trans-anti-benzo[a]pyrene adduct covalently attached to the G8 nucleotide in the sequence d(CCTATGT[BP-G]CAC).d(GTGCACATAGG) was synthesized and the structure characterized by one- and two-dimensional NMR spectroscopy, in conjunction with energy minimization and molecular dynamics. This BP-11-mer duplex exhibits NOESY cross-peaks between benzo[a]pyrene protons and BP-G8, C9, A16, and C17 nucleotide protons that clearly delineate the location of the BP moiety in the minor groove of a B-type duplex with the pyrene ring oriented toward the 5' end of the modified strand. Large upfield shifts of A16 and C17 sugar resonances in the partner strand show that the pyrene moiety is situated near these sugars. Analysis of the spectra was complicated by the presence of chemical exchange line broadening of protons located near the (...T[BP-G]C...).(...GCA...) adduct site which shows the presence of a minor conformation for this BP-modified duplex in which TA is the 5' neighboring base pair. Distance restraints determined from NOESY spectra recorded at 20 degrees C were used in restrained and unrestrained energy minimization and molecular dynamics simulations to obtain a structure characteristic of the predominant conformation of the BP-11-mer duplex. The important structural features of the BP-11-mer are similar to those reported by Cosman et al. [(1992) Proc. Natl. Acad. Sci. U.S.A. 89, 1914-1918] for a (+)-trans-anti-BP adduct at a (...C[BP-G]C...).(...GCG...) sequence in which CG is the 5' neighboring base pair. No evidence of a conformational equilibrium was reported in this duplex, from which we conclude that the presence of a 5' TA base pair plays a role in the conformational equilibrium. Watson-Crick base pairing is retained in the predominant conformer of the (+)-trans-anti-BP modified duplex, which provides a visualization of a structure that could allow faithful replication. The exchange rate could not be slowed sufficiently to allow individual distance parameters to be obtained for the minor conformer.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Structural characterization of a (+)-trans-anti-benzo[a]pyrene-DNA adduct using NMR, restrained energy minimization, and molecular dynamics. 788 Aug 10

To screen for mutations within the factor VIII gene of 101 patients (85 unrelated), we used denaturing gradient gel electrophoresis (DGGE) after DNA amplification of target regions, including all coding regions except for the middle part (amino acid 757 to amino acid 1649) of the B domain. With this method, missense mutations were identified in 86% of unrelated patients. 41 different mutations were identified: 25 of them have not been described previously. Five of the genotypes are associated with CRM+ and 26 with CRMred status. Patients who are definitely related to each other showed no differences in DNA sequence. One patient showed two different base pair alterations, the first at amino acid 469 [ala(GCA-->gly(GGA)] and the second at position 473 [tyr(TAT)-->cys(TGT)]. One patient with an amino acid change at position 1689 [arg(CGC)-->his(CAC)] has developed an inhibitor against factor VIII.
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PMID:Characterization of mutations within the factor VIII gene of 73 unrelated mild and moderate haemophiliacs. 854 94

In the present study we investigated the frequency of p16 gene exon 2 mutations in 35 malignant gliomas, using either direct sequencing of the PCR products or cloning into the pCRII vector and sequencing of the cloned PCR products. No mutations were detected during direct sequencing of the PCR products. However, after sequencing of individual clones, we found multiple mutations in 5 tumors involving codons 73(GCC to ACC, Ala to Thr), 76 (GCC to GTC, Ala to Val), 85(GCT to ACT, Ala to Thr), 98(CAC to TAC, His to Tyr), 102 (GCG to GTG, Ala to Val), 106 (GTG to ATG, Val to Met), 107 (CGC to TGC, Arg to Cys), 127 (GCA to GTA, Ala to Val), 128 (CGG to TGG, Arg to Trp) and 136 (GGC to GAC, Gly to Asp). Mutations were found only in glioblastomas and were either C to T or G to A transitions. Each mutation was detected in a small percentage of tumor cells (1.3-22%) using individual colony sequencing and southern hybridization with mutant oligonucleotides, consistent with the heterogenous cell population of glioblastomas. The presence of p16 gene mutations only in glioblastomas suggests that they are late events in glioma development.
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PMID:Mutations of the p16 gene in gliomas. 855

The sequence specificity of DNA-binding by monoaza- and diaza-anthracenedione analogues of mitoxantrone (MX) has been investigated by DNase 1 footprinting and spectroscopic techniques. More than 100 sites cut by the enzyme were sequenced on three pBR 322 and simian virus 40 DNA restriction fragments. Different inhibition and stimulation effects were observed as a function of the structural properties of each drug. A gradual change was found from MX to monoaza derivatives and from these to diaza derivatives, corresponding to a broader distribution of drug-inhibited regions. In addition to almost all sites found with MX (38 of 44), 29 new inhibition sites were observed using the diaza compound BBR 2894. The sequence analyses in terms of base doublets or triplets confirm the preference of MX for alternating pyrimidine-purine sites, the most significant triplet sequences being (5' to 3') CTA, GCA, TAC, ACT, CAC and TTA. In addition to MX sites, BBR 2894 seemed to bind efficiently to pyrimidine-pyrimidine-pyrimidine or purine-pyrimidine-pyrimidine triplets containing CT or TC motifs. Differential cleavage plots essentially confirmed the above results. Spectrophotometric and chiroptical studies showed a decreased DNA-binding affinity and a modified geometry of intercalation when nitrogen replaces carbon in the anthraquinone ring. These results can be useful for understanding the substantially different biological responses exhibited by aza-substituted anthracenedlones when compared with their non-substituted, pharmacologically relevant congeners.
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PMID:Aza-bioisosteres of 9, 10-anthracenedione: a modulation of DNA sequence specificity. 886 28

Little is known about the presence of common medical pathogens in the human oral cavity. Using a 16S rRNA-based PCR identification method, this study determined the occurrence of Porphyromonas asaccharolytica, Bacteroides fragilis and Chlamydia pneumoniae in subgingival plaque from 50 adults with advanced periodontitis. Each patient contributed samples from 3 deep periodontal pockets collected by paper points. The PCR primers were for P. asaccharolytica 5'-CTC TAG CTA GAG TGT ACT GG-3' and 5'-ATA GGG TTT ATA GAT TAG CTC TCT-3', for B. fragilis 5'-AAT GAT TCC GCA TGG TTT CAT TA-3' and 5'-GCG GTG ATT GCT CAC TGA CA-3', and for C. pneumoniae 5'- TGA CAA CTG TAG AAA TAC AGC-3' and 5'-CGC CTC TCT CCT ATA AAT-3'. The primers yielded a single amplicon with the respective reference strains and produced no amplicon with colonies of 25 groups of oral organisms. None of the three test species were detected in any of the 50 pooled subgingival samples tested. P. asaccharyolytica, B. fragilis and C. pneumoniae do not seem to be part of the periodontopathic microbiota in humans.
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PMID:Absence of Porphyromonas asaccharolytica, Bacteroides fragilis and Chlamydia pneumoniae in human subgingival plaque. 957 14

Hb G-Coushatta [beta22(B4)Glu-->Ala] is found in geographically separated ethnic groups. Commonest along the Silk Road region of China but also present in the North American Coushatta, we sought to determine whether this variant had a unicentric or multicentric origin. We examined the haplotype of the beta-globin gene cluster in two Chinese families and in five Louisiana Coushatta heterozygous for this mutation. Chinese and Louisiana Coushatta had different haplotypes associated with the identical Hb G mutation. These haplotypes were defined by the presence of a HindIII restriction site in the Agamma-globin gene and AvaII restriction site in the beta-globin gene in Chinese subjects and their absence in the Louisiana Coushatta. We found a CAC at codon beta2 (beta-globin gene framework 1 or 2) linked to the Hb G-Coushatta gene in Chinese, and a CAT (framework 3) in Louisiana Coushatta, indicating different beta-globin gene frameworks. Both the Hb G-Coushatta mutation (GAA-->GCA) and the codon 2 CAC-->CAT polymorphism are normal delta-globin gene sequences, suggesting the possibility of gene conversion. We conclude that Hb G-Coushatta had at least two independent origins. This could be due to separate mutations at codon beta22 in Chinese and Louisiana Coushatta, a mutation at this codon and a beta-->delta conversion, or two beta-->delta gene conversion events.
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PMID:Genetic studies suggest a multicentric origin for Hb G-Coushatta [beta22(B4)Glu-->Ala]. 1008 86

The finding that a lens under oxidative stress accumulated free and protein-bound cysteine (protein-S-S-cysteine) in the fiber cells prompted us to examine if there is an alternative source for cysteine pools besides the active cysteine transport system in the lens, namely, the transsulfuration pathway of homocysteine-cystathionine-cysteine, which utilises methionine through transmethylation. We examined the presence of the gene for cystathionine-beta-synthase (CBS), the rate limiting enzyme that converts homocysteine to cystathionine in the transsulfuration pathway, in human lens epithelial (HLE) B3 cells using PCR with primers designed based on the sequence of human liver CBS (Forward 5'-CCA CAC TGC CCC GGC AAA AT-3'; Reverse 5'-CTG GCA ATG CCC GTG ATG GT-3'). The purified DNA fragment (586 bp) from PCR analysis was sequenced and confirmed the homology with CBS gene from other human tissues. The CBS protein band (67 kDa) was present in the HLE cells, which reacted positively with the human liver anti-CBS antibody. The enzyme protein was detected in the pig and human lenses with the highest intensity in the epithelial layer, lower but equal quantities of CBS was present in the cortical and nuclear regions. Human nuclear CBS increased while epithelial CBS decreased with aging. Oxidative stress transiently upregulated the gene expression of CBS both in HLE cells (0.1 mMH2O2) and in pig lens cultured in TC 199 medium (0.5 mMH2O2). The catalytic activity for CBS, which was assayed by measuring the production of C14-cystathionine from C14-serine in the presence of homocysteine, S-adenosyl-methionine and pyridoxal phosphate, was detectable in the HLE cells and transiently activated with H2O2. Free cystathionine accumulated when HLE B3 cells were treated with propargylglycine (PGG), an inhibitor of cystathionase, the downstream enzyme that converts cystathionine to cysteine. More cystathionine accumulation occurred when the cells were simultaneously exposed to PGG and 0.1 mMH2O2. We have shown that oxidative stress of H2O2 could increase the flux of this transsulfuration pathway by committing more homocysteine to cysteine and glutathione production as H2O2 (0.1 mM) inhibited the remethylation enzyme of methionine synthase while concurrently activating the CBS enzyme. This is the first evidence that a transsulfuration pathway is present in the lens, and that it can be upregulated under oxidative stress to provide additional redox potential for the cells.
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PMID:The presence of a transsulfuration pathway in the lens: a new oxidative stress defense system. 1564 25

Using a plasmid transformation method and the RM search computer program, four type I restriction enzymes with new recognition sites and two isoschizomers (EcoBI and Eco377I) were identified in a collection of clinical Escherichia coli isolates. These new enzymes were designated Eco394I, Eco826I, Eco851I and Eco912I. Their recognition sequences were determined to be GAC(5N)RTAAY, GCA(6N)CTGA, GTCA(6N)TGAY and CAC(5N)TGGC, respectively. A methylation sensitivity assay, using various synthetic oligonucleotides, was used to identify the adenines that prevent cleavage when methylated (underlined). These results suggest that type I enzymes are abundant in E.coli and many other bacteria, as has been inferred from bacterial genome sequencing projects.
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PMID:Four new type I restriction enzymes identified in Escherichia coli clinical isolates. 1604 May 96

HLA-C was shown to be a highly polymorphic gene that can be accurately typed by sequencing methodologies. We report two novel HLA-C alleles identified during sequence-based typing of East African populations; the novel alleles were confirmed by sequencing two separate polymerase chain reaction products and by molecular cloning and sequencing multiple clones. The first new allele is identical to Cw*0701 except for a single-nucleotide synonymous substitution at codon 182 (GCA-->GCG). The new allele has been named by the WHO nomenclature committee as Cw*070105. The second new allele is identical to Cw*1403 except for a nonsynonomous change at codon 21 (CAC-->CGC), changed from histidine to arginine. The new allele has been named by the WHO nomenclature committee as Cw*1408.
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PMID:Identification of two novel HLA-C alleles, Cw*070105 and Cw*1408, from East African women. 1672 Feb 18

By using lumichrome (Lch) as a masking ligand, we successfully control the binding selectivity of 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) when binding to nucleobases in AP site-containing DNA duplexes (5'-TCT GCG TCC AGX GCA ACG CAC AC-3'/3'-AGA CGC AGG TCN CGT TGC GTG TG-5', X = AP site; Spacer C3, N = C or T). In solutions buffered to pH 7.0 (I = 0.11 M, at 5 degrees C), ATMND binds to cytosine and thymine with a comparable binding affinity (K(d) / nM: C: 7.7, T: 15). By contrast, in the presence of Lch, ATMND shows a clear binding selectivity for cytosine over thymine (K(d)/nM: C: 17, T: 204). Such competitive binding events are discussed with a view towards development of ligand-based fluorescence assay for single-nucleotide polymorphisms (SNPs) typing.
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PMID:Competitive binding of small ligands to nucleobases in AP site-containing DNA duplexes. 1877 82


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