Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A polyclonal, monospecific antibody to a constitutive, diabetes-inducible and insulin-reversible cytochrome P-450 isozyme (RLM6) was used to screen a male rat liver cDNA library in lambda gt 11. Six clones harbouring the RLM6 cDNA insert were isolated initially from the expression library and three of these were further plaque-purified and sub-cloned. A 1.1 Kb cDNA insert, representing approximately 65% of the expected full length cDNA was characterized by restriction endonuclease mapping and sequenced by the dideoxy chain-termination method. Comparison of the nucleotide sequence of RLM6 cDNA to that of ethanol-inducible P4502E1 rat cDNA showed the two cDNAs to be identical, the RLM6 cDNA corresponding to nucleotides 310-1402 of the P4502E1 sequence. 2. RLM6 cDNA probe was used in Northern blot and RNA dot blot hybridization analysis to demonstrate that both streptozotocin-induced diabetes and fasting significantly elevated the steady-state level of RLM6 mRNA in male rat liver. Increased RLM6 mRNA level in the diabetic rat resulted in increased RLM6 apoprotein synthesis when polysomal RNA was used in a cell-free, protein-synthesizing system, indicating that the elevated RLM6 level observed in diabetic rats was correlated directly with the increased RLM6 mRNA concentration. 3. Daily insulin treatment of diabetic rats reversed the diabetes-dependent increase in RLM6 mRNA in a time-dependent manner, returning to control values after approximately 2 weeks of continuous insulin treatment. This insulin-dependent decrease of the RLM6 mRNA level was paralleled by a similar time-dependent decrease in serum acetone concentration. 4. Treatment of the male diabetic rat with testosterone also resulted in a decrease in both RLM6 mRNA and in vitro translated apoprotein. 5. Modulation of RLM6 mRNA level in the diabetic rat by insulin and testosterone, and the nucleotide sequence similarity with that of P4502E1 confirms that diabetes-inducible P450RLM6 and ethanol-inducible P4502E1 are coded for by the same gene.
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PMID:Molecular cloning of a cDNA for rat diabetes-inducible cytochrome P450RLM6: hormonal regulation and similarity to the cytochrome P4502E1 gene. 144 86

The final step in aldosterone biosynthesis, an oxidation at position 18 of 18-hydroxycorticosterone, is catalyzed by an enzymatic activity termed corticosterone methyl oxidase II (CMO II). This activity is mediated in vitro by P450c11 (steroid 11-hydroxylase), a cytochrome P-450 enzyme that also catalyzes the preceding two steps of 11-hydroxylation and 18-hydroxylation. CMO II deficiency, an inherited defect in the 18-oxidation step, impairs aldosterone biosynthesis and thus leads to a clinical syndrome of salt wasting. To test the hypothesis that CMO II deficiency results from a mutation affecting the structural gene for P450c11, we examined 11 affected and 21 unaffected members of six families with this disorder. After DNA samples were digested with the restriction endonuclease MspI (thereby cutting the DNA at specific sites) and hybridized with a P450c11 DNA probe, a unique DNA fragment in the P450c11 structural gene was detected in subjects with the deficiency. The DNA fragment and the disease trait were inherited together in each family, demonstrating that CMO II deficiency is caused by a mutation in or very near the structural gene for P450c11 on chromosome 8. We conclude that the metabolic diseases of CMO II and 11-hydroxylase deficiency, which have distinct clinical symptoms, may be caused by different mutations in the single gene for a multifunctional enzyme.
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PMID:An inherited defect in aldosterone biosynthesis caused by a mutation in or near the gene for steroid 11-hydroxylase. 326 27

A search for uncharacterized genes of the S region of the murine H-2 major histocompatibility complex was undertaken; a series of cosmid clones previously aligned by overlap hybridizations were used as radiolabeled probes. Sequences hybridizing with liver poly(A)+ RNA were found within a cosmid covering a region 3' to the C4-Slp gene (the gene encoding the hemolytically inactive isoform of the fourth component of serum complement). Radiolabeled, short cDNA complementary to liver poly(A)+ RNA was used to establish the transcriptional polarity of the newly detected gene and to define fragments containing its 3' end. DNA sequence analyses and comparisons with porcine peptides established that the gene encodes the enzyme steroid 21-hydroxylase (EC 1.14.99.10), a cytochrome P-450 often referred to as P-450(C21), whose major site of expression is the adrenal gland. Two copies of the P-450(C21) gene, very similar yet distinguishable by restriction endonuclease analysis, were found individually associated with C4 and C4-Slp, genes that encode isoforms of mouse fourth component of complement. One of the P-450(C21) genes is coamplified with C4-Slp in H-2w7, a haplotype carrying a rare elongation of the S region. Comparisons with other members of the P-450 gene family show that the P-450(C21) genes encode peptides of extraordinary evolutionary conservation. The detection of a liver transcript of P-450(C21) raises the issue of the specific metabolic role of this enzyme in this organ and may have implications for the interpretation of human congenital adrenal hyperplasia.
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PMID:Liver mRNA probes disclose two cytochrome P-450 genes duplicated in tandem with the complement C4 loci of the mouse H-2S region. 387 1

A differential screening procedure was employed to isolate a cDNA clone corresponding to a major phenobarbital (PB)-inducible form of rat hepatic cytochrome P-450. The G-C homopolymer-tailing technique was utilized to construct a cDNA library in the PstI site of plasmid pBR322. The library represented PB-induced poly(A+)RNA sequences from hepatic polysomes of 150-g male Sprague-Dawley rats. Hybrid-selection experiments against total PB-inducible RNA were performed with plasmid DNA derived from clones enriched in PB-inducible information. The mRNA molecules that specifically hybridized were subjected to in vitro translation, were immunoprecipitated with antibody raised in rabbits against purified cytochrome P-450b (P. E. Thomas, D. Korzeniowski, D. Ryan, and W. Levin (1979) Arch. Biochem. Biophys. 192, 524-532), and were electrophoresed under sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoretic conditions. One cDNA clone, designated PB-8, contained a 600-bp insert partially coding for a PB-inducible cytochrome P-450 species that comigrated on SDS-gel electrophoresis with highly purified P-450b. A single injection of PB, 15-18 h before sacrifice, increased the level of polysomal poly(A+)RNA complementary to the isolated cDNA clone by approximately 16-fold. Northern blot hybridizations of polysome-derived poly (A+)RNA, electrophoresed in denaturing agarose gels, demonstrated that the size of the mRNA corresponding to the isolated clone was 4 kb. Isolated heteronuclear RNA species demonstrated a time-dependent increase in the synthesis of a similar 4-kb RNA molecule. By genomic blot hybridization to EcoRI-restricted DNA, at least three complementary DNA fragments migrating at 5.1, 3.2, and 2.9 kb were observed with 32P-labeled PB-8 as a probe. These data, together with restriction endonuclease mapping and partial cDNA sequence information of the PB-8 cDNA, suggest that the PB-8 clone represents a previously unreported cDNA clone for a form of cytochrome P-450 inducible by PB.
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PMID:Molecular induction by phenobarbital of a rat hepatic form of cytochrome P-450: expression of a 4-kilobase messenger RNA. 614 64

We have determined the molecular genetic basis of congenital adrenal hyperplasia due to 21-hydroxylase (21-OHase) deficiency. This common disorder of cortisol biosynthesis is HLA-linked. The haplotype HLA-(A3);Bw47;DR7 is strongly associated with 21-OHase deficiency and always carries a null allele at the locus encoding the C4A (Rodgers) form of the fourth component (C4) of complement. It seemed likely that this haplotype carries a deletion encompassing the genes encoding both C4A and 21-OHase. We hypothesized that the HLA-linked defect involved a structural gene for the adrenal microsomal cytochrome P-450 specific for steroid 21-hydroxylation. Using a plasmid with a 520-base-pair bovine adrenal cDNA insert encoding the middle third of the cytochrome P-450 polypeptide, we compared hybridization patterns in DNA from normal and 21-OHase-deficient individuals. Normal human DNA yielded two fragments that hybridized with the probe after digestion with either restriction endonuclease EcoRI [12- and 14-kilobase (kb) fragments] or Taq I (3.7 and 3.2 kb). One of these bands (the first mentioned in each digest) was absent in DNA from a cell line derived from a patient homozygous for HLA-Bw47. DNA from six unrelated patients homozygous for 21-OHase deficiency who were heterozygous for HLA-Bw47 yielded diminished relative intensity of the 3.7-kb Taq I band in five patients, consistent with a heterozygous deletion, and complete disappearance of the 3.7-kb band in one. This deletion segregated with HLA-Bw47 in a large pedigree carrying 21-OHase deficiency and HLA-Bw47. Thus, 21-OHase deficiency sometimes results from the deletion of a specific cytochrome P-450 gene and sometimes, presumably, from smaller mutations. This gene is probably located very near the C4A gene.
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PMID:HLA-linked congenital adrenal hyperplasia results from a defective gene encoding a cytochrome P-450 specific for steroid 21-hydroxylation. 633 10

Congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency is HLA-linked. The haplotype HLA-(A3);Bw47;DR7 is strongly associated with 21-OH deficiency and always carries a null allele at the complement C4A (Rodgers) locus. It seemed likely that this haplotype carries a deletion encompassing both the C4A and 21-OH loci. We hypothesized that the HLA-linked defect involved a structural gene for the adrenal microsomal cytochrome P-450 specific for steroid 21-hydroxylation. We isolated a plasmid with a 520 bp bovine adrenal cDNA insert encoding the middle third of the P-450 peptide. When human DNA was digested with Taq I restriction endonuclease and hybridized with the cDNA probe, DNA from 13 unrelated normal individuals yielded two hybridizing bands of equal intensity at 3.7 and 3.2 kb. The upper band was not present in DNA from a patient homozygous for Bw47. DNA from six unrelated patients heterozygous for Bw47 yielded, in five, diminished relative intensity of the upper band consistent with a heterozygous deletion, and complete disappearance of the upper band in one. Thus 21-OH deficiency sometimes results from the deletion of a gene and sometimes, presumably, from smaller mutations. This gene is probably located very near the C4A gene encoding the 4th component of complement.
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PMID:Molecular cloning of steroid 21-hydroxylase. 633 60

A 7.0-kb DNA fragment that conferred redbrown pigment production on Streptomyces griseus was shotgun-cloned with a multicopy vector pIJ486 from this microorganism. By restriction endonuclease mapping and subcloning, a 1.5-kb fragment which is essential for the production of redbrown pigment was determined. The nucleotide sequence of this region revealed the presence of two open reading frames, ORF1 with 109 amino acids (named RppA) and ORF2 with 262 amino acids (RppB), in addition to a truncated ORF3. The termination codon of rppA and the initiation codon of rppB overlapped, sharing one common nucleotide, which strongly suggests that these two genes are cotranscribed. Both rppA and rppB were essentially required for the pigmentation. The RppB protein showed great similarity in amino acid sequence to a chalcone synthase, a key enzyme of central importance in the biosynthetic pathway of all classes of flavonoids in plants. Part of RppA showed sequence similarity to the 33kDa phosphoprotein of adenovirus. Nucleotide sequences homologous to rppA and rppB were widely distributed in Streptomyces species, as determined by Southern hybridization. Further nucleotide sequencing of the entire orf-3 gene showed that ORF3 with 403 amino acids was a cytochrome P-450 (named P-450RPP). These data suggested that the cloned fragment contained part of a gene cluster for the biosynthesis of a certain metabolite. Introduction of the subcloned 1.5-kb fragment into Streptomyces lividans as well as Escherichia coli also caused production of redbrown pigment, suggesting that RppA and RppB are capable of synthesizing the redbrown pigment from metabolites commonly present in bacteria.
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PMID:Overexpression of a gene cluster encoding a chalcone synthase-like protein confers redbrown pigment production in Streptomyces griseus. 764 62

Despite a wide interindividual variation of cytochrome P-450 1A2 (CYP1A2) activity, genetic polymorphism of CYP1A2 has not been reported. By amplification of exons of CYP1A2 by polymerase chain reaction in eight Chinese subjects, the polymerase chain reaction products were directly sequenced. One subject showed heterozygous C2866-->G (Phe21-->Leu) polymorphism. DNA from 157 Chinese subjects (104 polychlorinated biphenyl-exposed subjects and 53 control subjects) was screened for polymorphism by single-strand conformation polymorphism method and MboII endonuclease digestion. Only 1 of 157 samples showed another heterozygous C2866-->G mutation. The subject was previously exposed to polychlorinated biphenyl and showed a value of 3.5% in the caffeine breath test. The value is not significantly higher than the mean value of polychlorinated biphenyl-exposed subjects (3.12 +/- 0.29%, mean +/- S.E.M.). The incidence of the point mutation in these Chinese subjects is less than 1%. The prevalence of the F21L mutation in other ethnic groups and its effect on the metabolic activity of CYP1A2 remain to be further evaluated.
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PMID:Detection of a novel cytochrome P-450 1A2 polymorphism (F21L) in Chinese. 988 16