Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast L(+)-lactate cytochrome c oxidoreductase or cytochrome b2 is a component of the mitochondrial intermembrane space. The protein is encoded by the nuclear genome, synthesized as a larger precursor in the cytoplasmic compartment, and then proteolytically processed to its mature form during its import into the mitochondria. The structural gene for yeast cytochrome b2 has been cloned. The complete nucleotide sequence of the gene with its 5' and 3' flanking regions was determined. The deduced primary structure of the cytochrome b2 precursor reveals an unusually long amino terminal extension of 80 amino acids. A variety of potentially significant sequences were identified in the region flanking the structural portion of the gene. Transcript mapping with both S1 nuclease and primer extension methods reveals that the site of RNA synthesis is 56-66 bp downstream from a putative TATA box. By Northern blot analysis and gene disruption, it is shown that there is only a single copy of the cytochrome b2 gene per haploid yeast nucleus. The cloned cytochrome b2 gene was used to probe specific mRNA levels and demonstrate that cytochrome b2 expression is transcriptionally repressed by glucose and induced by lactate. The inactivation of the chromosomal cytochrome b2 gene by integrative transformation led to a deficiency in L(+)-lactate dehydrogenase activity and consequently to the inability to use L(+)-lactate as a sole source of carbon. This is the first reported mutation affecting the structural gene of cytochrome b2.
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PMID:Structure, expression and regulation of a nuclear gene encoding a mitochondrial protein: the yeast L(+)-lactate cytochrome c oxidoreductase (cytochrome b2). 300 48

The nucleotide sequence of a 2.5 X 10(3)-base segment of yeast nuclear DNA, containing the structural gene for the 40-kDa subunit II of the ubiquinol:cytochrome-c oxidoreductase, has been determined. The region contains only one single reading frame of length sufficient to encode a protein of the size of subunit II. The mature protein is predicted to have a length of 352 amino acids, with a molecular mass of 38714 Da. It is predominantly hydrophilic, with an overall polarity of 45%. Comparison of the sequence of the reading frame with that derived from direct sequence analysis of the N terminus of the mature 40-kDa protein shows that subunit II is synthesized as a longer precursor and shows that the extension is N-terminal. The presequence is 16 amino acids long and it contains a number of positively charged residues and lacks acidic ones. It is also rich in neutral, polar amino acids. S1 nuclease protection analysis of DNA X RNA hybrids identifies two major and one minor transcript of the gene, whose 5' termini map approximately 55, 65 and 75 nucleotides upstream of the initiation codon. Sequences 5' of these termini lack obvious homology to the regulatory sequences of other imported mitochondrial proteins, whose synthesis is controlled by oxygen and by catabolite repression. A mutant lacking a functional subunit II gene has been constructed by a one-step gene-disruption procedure. This mutant grows only slowly on glycerol and still displays a low level of QH2: cytochrome-c oxidoreductase activity (approx. 5% of that of wild type). The implications of this finding for the possible role of subunit II in the complex are discussed.
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PMID:Subunit II of yeast QH2:cytochrome-c oxidoreductase. Nucleotide sequence of the gene and features of the protein. 302 97

The nucleotide sequence of the gene encoding the 11-kDa subunit VIII of the ubiquinol-cytochrome-c oxidoreductase in Saccharomyces cerevisiae has been determined. The coding sequence has a length of 330 bp and is preceded at a distance of 361 bp by another reading frame, coding for a protein of as yet unknown function. The 11-kDa gene is transcribed independently of the URFx gene and transcription of both is sensitive to catabolite repression. Multiple 5' and 3' termini of transcripts of the gene for the 11-kDa subunit were identified by S1 nuclease protection analysis of DNA X RNA hybrids. The 5' termini map 52 +/- 2 and 60 +/- 2 nucleotides upstream of the initiation codon whereas the 3' termini map 336 +/- 2 and 350 +/- 2 nucleotides downstream of the stop codon. The subunit VIII reading frame encodes a protein with a molecular mass of 12.4 kDa and a polarity of 37.6%. It is predicted to contain a high content of beta-sheet segments, which may be capable of forming a barrel-like structure in a lipid bilayer. A comparison of the sequence with those of the small subunits of the beef heart complex reveals similarity with the 9.5-kDa subunit VII (core-linked protein) characterized by Borchart et al. (1986) FEBS Lett. 200, 81-86. The significance of this is discussed.
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PMID:Nucleotide sequence of the gene encoding the 11-kDa subunit of the ubiquinol-cytochrome-c oxidoreductase in Saccharomyces cerevisiae. 303 7

A rat liver DNA genomic library was prepared using the lambda phage cloning vector Charon 28. Recombinant phage were screened with a cDNA clone (pOR-7) containing sequences complementary to mRNA coding for NADPH-cytochrome P-450 oxidoreductase. This cDNA clone contains the poly(A) addition site and 60% of the mRNA sequence (Gonzalez, F. J., and Kasper, C. B. (1982) J. Biol. Chem. 257, 5962-5968). Four positive phage were identifed and plaque-purified, and their DNA was isolated and subjected to restriction endonuclease mapping. All phage DNA inserts, which ranged from 11 to 16 kilobases, contained several overlapping restriction fragments. The clone with the largest insert (lambda OR-2) was found to contain restriction fragments identical with those of rat DNA when both were subjected to Southern blotting with nick-translated pOR-7 DNA; this finding established the presence in lambda OR-2 of the 3' end (poly(A) addition site) of the oxidoreductase gene. When [32P]cDNA synthesized from enriched oxidoreductase poly(A) RNA was utilized as a probe, additional fragments were identified. The fragment most distal to the 3'-specific fragment was assumed to contain the 5' cap site and was subcloned into pBR322 for further analysis. Restriction mapping and Southern blot analysis further localized the 5' end of the gene to an AvaII fragment of 540 base pairs (bp). Hybridization of this fragment with oxidoreductase mRNA-enriched poly(A) RNA resulted in the arrest of translation of oxidoreductase; this confirmed that it contained an exon region of the oxidoreductase gene. S1 nuclease mapping and DNA sequencing identified to within +/- 1 bp the 5' cap site of the gene which corresponds to an A start. DNA sequencing of the 5'p flanking region revealed no "TATA box" in the vicinity of -25 to -30 bp of the cap site. R-loop analysis of lambda OR-2 revealed the presence of a minimum of seven introns in the 6000-bp oxidoreductase gene and eight exons with a total length of approximately 2600 bp.
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PMID:Cloning and characterization of the rat NADPH-cytochrome P-450 oxidoreductase gene. 629 77

We previously characterized and cloned a unique human hepatic dihydrodiol dehydrogenase (DDH) that exhibits high affinity binding for bile acids (Stolz, A., Hammond, L., Lou, H., Takikawa, H., Ronk, M., and Shively, J. E. (1993) J. Biol. Chem. 268, 10448-10457). This hepatic dihydrodiol dehydrogenase demonstrates significant sequence homology with the cytosolic rat bile acid binder 3 alpha-hydroxysteroid dehydrogenase and other members of the monomeric oxidoreductase gene family. We now report the genomic organization and chromosomal localization of the human hepatic DDH in order to further define its physiological role and provide additional insight into the development of this gene family. The 15-kilobase human hepatic DDH gene was contained in an overlapping cosmid and lambda genomic clones and is composed of nine exons. A major transcriptional start site was determined to be 30 base pairs upstream from the ATG initiation methionine by both primer extension and S1 nuclease mapping studies. The human hepatic DDH gene was mapped by chromosomal in situ hybridization and analysis of human-mouse somatic cell hybrids to the tip of the short arm of chromosome 10 at p14. Strict conservation of the intron-exon junctions in the human hepatic DDH and two other members of the monomeric oxidoreductase gene family, aldose reductase and mouse major vas deferens protein suggests evolution from a common ancestral gene. Human hepatic DDH mRNA was identified in both human hepatoma Hep G2 and human lung carcinoma cell line NCI-H322 by RN'ase protection; thus, these cell lines will be useful in examining the regulation of the gene.
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PMID:Genomic organization and chromosomal localization of a novel human hepatic dihydrodiol dehydrogenase with high affinity bile acid binding. 813 67

The untranslated first exon and the 5'-flanking region for the rat liver NADPH-cytochrome P450 oxidoreductase gene has been isolated from a Wistar-Furth genomic library. The remainder of the gene is composed of 15 exons which code for the mature protein and a 3'-nontranslated segment (T. D. Porter et al. Biochemistry, 1990, 29, 9814-9818). The 56-bp first exon resides 30.5 kb upstream from exon two, making the total gene length approximately 50 kb. While the region surrounding the start site (TCAGAGAC) was found to be homologous to a eukaryotic cap signal, the 5' flanking region possesses neither a TATA nor a CCAAT box. Instead it contains five GC-rich hexanucleotide consensus sequences for the transcription factor Sp1. These features clearly distinguish it from genes encoding other members of the mixed-function oxidase system, the cytochromes P450. Primer extension analysis and S1 nuclease mapping identified multiple transcriptional start sites. In many respects, the TATA-less oxidoreductase promoter resembles the promoter regions of dihydrofolate reductase and other housekeeping genes. Northern blot analysis demonstrates that this promoter is modulated by phenobarbital and trans-stilbene oxide, known inducers of oxidoreductase.
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PMID:NADPH cytochrome P-450 oxidoreductase gene: identification and characterization of the promoter region. 817 32