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)

Sequencing of an open reading frame associated with cytoplasmic male sterility (CMS) in Petunia has revealed a gene fusion (the Pcf gene) containing the 5'-flanking and amino-terminal transmembrane segment of the ATP synthase proteolipid gene (atp9), parts of the cytochrome oxidase subunit II (coxII) coding region, and the carboxyl terminus and 3'-flanking region of an unidentified reading frame (urfS). The coxII region has several small deletions and tandem repeats that remove all of the segments coding for the residues involved in copper binding, but may possibly maintain the cytochrome c binding site. Normal atp9 and coxII genes and their transcripts are also present in the sterile cytoplasm. S1 nuclease protection studies identify fused gene transcripts only in CMS lines, with an increase in transcript amount in anthers relative to leaves.
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PMID:A fused mitochondrial gene associated with cytoplasmic male sterility is developmentally regulated. 288 95

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

Production of 10-base multiple DNA ladder fragments during DNase I digestion of chromatin is explained by a model which does not involve site-specific nicking by the DNase I. This model was tested because it explains why 10-base (actually 10.4 base) multiple-related fragments are paradoxically generated by both endonucleolytic (DNase I) and exonucleolytic (exonuclease III) mechanisms. This new model also explains the phenomenon of substantial single-stranded DNA production during DNase I digestion of chromatin. The latter phenomenon has been widely observed but is not explained by previous models. The single-stranded gap model to be presented makes testable predictions. Primarily, these are that DNase I produces single-stranded gaps in chromatin DNA and that the termini of 10-base multiple ladder fragments are separated by single-stranded gaps. Single-stranded gap production by DNase I was confirmed by a number of methods. Sensitivity of ladder band components (from DNase I but not staphylococcal nuclease digests) to S1 nuclease suggested that the ladder fragments themselves may compose a significant portion of these gaps. Separation of ladder fragment termini by single-stranded gaps was verified by demonstrating both resistance to the nick-specific NAD+-dependent ligase and sensitivity to T4 ligase which can ligate across gaps. Many single-stranded gaps, occurring both individually and clusters, were observed by electron microscopy using either cytochrome c labeling (where the gaps) are thinner than duplex) or gene 32 protein labeling (gaps thicker than duplex). Gap sizes were estimated by protecting them with gene 32 protein and digesting away unprotected duplexes. By this method, gap sizes fall into a ladder distribution (from 10 or 20 bases up to 120 bases), which, at least in the region of the shorter sizes, clearly indicates the sizes of single-stranded gaps formed in chromatin by DNase I.
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PMID:Deoxyribonuclease I generates single-stranded gaps in chromatin deoxyribonucleic acid. 624 43

Nuclear respiratory factor 1 (NRF-1) is a transcription factor that acts on nuclear genes encoding respiratory subunits and components of the mitochondrial transcription and replication machinery. Here we describe the isolation and characterization of the human gene encoding NRF-1. The human genomic sequences detected with NRF-1 cDNA probes at high stringency are all contained within seven overlapping recombinant lambda clones. The NRF-1 gene encompassed by these recombinants spans approximately 65 kilobases (kb) and has 11 exons and 10 introns that range in size from 0.8 to 15 kb. A rapid amplification of cDNA ends-polymerase chain reaction product containing the 5'-terminus of the NRF-1 cDNA has two exons from the 5'-untranslated region and terminates at a major transcription initiation site identified by S1 nuclease mapping. A genomic fragment containing a portion of the 5'-terminal exon and an additional 1 kb upstream had a functional promoter that was active in transfected COS cells, HeLa cells, and L6 myoblasts. The transcription initiation site utilized by the transfected promoter corresponded to that used by the endogenous gene in vivo. NRF-1 mRNA was expressed at very low levels in rat tissues compared with cytochrome c and, unlike cytochrome c, was most abundantly expressed in lung and testis. The NRF-1 gene was localized to human chromosome 7 by analysis of DNA from a panel of human-hamster cell hybrids with human-specific NRF-1 polymerase chain reaction primers. This assignment was further refined to 7q31 by cohybridization of NRF-1- and chromosome 7-specific probes to human metaphase chromosomes. These analyses should be useful in evaluating the potential role of NRF-1 in mitochondrial diseases resulting from defects in the nuclear control of mitochondrial function.
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PMID:Structure, expression, and chromosomal assignment of the human gene encoding nuclear respiratory factor 1. 762 10