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

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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 structural gene (fdxN) encoding ferredoxin I (FdI) in the photosynthetic bacterium Rhodobacter capsulatus was isolated from a cosmid library by using an oligonucleotide probe corresponding to the N-terminal amino acid sequence of FdI. The nucleotide sequences of the gene and of the 3'- and 5'-flanking regions were determined. The gene fdxN codes for a polypeptide of 64 mino acids having a calculated molecular weight of 6,728. Amino acid sequencing of the N- and C-terminal ends of FdI allowed the determination of 86% of the primary structure and confirmed that FdI is the fdxN gene product. Sequence comparisons indicate that FdI shares common structural features with ferredoxins containing two [4Fe-4S] clusters, including eight conserved cysteines. Maximal homology was found with a ferredoxin from Rhodo-pseudomonas palustris. Northern (RNA) hybridization using a 158-base-pair DNA fragment internal to the fdxN coding region revealed the existence of two mRNA transcripts of approximately 330 and 750 nucleotides. Neither of those transcripts was present under nif-repressing growth conditions. The 5' end of the smaller transcript was mapped by S1 nuclease protection and primer extension experiments. On the basis of Southern hybridization experiments, by using probes homologous to fdxN, nifE, and a fragment complementing a nif point mutation, fdxN was localized inside a cluster of nif genes.
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PMID:Molecular cloning and sequence analysis of the structural gene of ferredoxin I from the photosynthetic bacterium Rhodobacter capsulatus. 268 Nov 57

A novel virus isolated from the feather follicles of cockatoos diagnosed as having psittacine beak and feather disease was characterized by electron microscopy, nucleic acid content, and polypeptide composition. Purified virions displayed an icosahedral symmetry, were nonenveloped, and had a mean diameter of 14 to 16 nm negatively stained. Three major viral proteins were identified, with approximate molecular weights of 26.3, 23.7, and 15.9 kDa. The viral nucleic acid was found to be single-stranded DNA based on acridine orange staining, resistance to alkali and ribonuclease, and sensitivity to both DNAse 1 and S1 nuclease. The size of the DNA was estimated to be between 1.7 and 2.0 kb by agarose gel electrophoresis. This size and its circular conformation were confirmed by electron microscopy. A preliminary transmission study using purified virus induced pathological lesions characteristic of those observed in the natural disease. On the basis of the extremely small size of the virions and the single-stranded circular viral DNA, we propose that the etiologic agent of psittacine beak and feather disease represents a previously undescribed viral pathogen.
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PMID:Characterization of a new virus from cockatoos with psittacine beak and feather disease. 274 50

Cardiac troponin C (cTnC) is the calcium-binding subunit of the myofibrillar thin filament that regulates excitation-contraction coupling in cardiac muscle. We have utilized a novel polymerase chain reaction cloning procedure to isolate cDNA clones encoding murine cTnC. Murine cTnC is a 161-amino acid polypeptide that has been highly conserved during evolution. Southern blot analyses demonstrated that the cTnC gene is a member of a multigene family. Northern blot analyses revealed that the cTnC gene is expressed in murine cardiac tissue and slow skeletal muscle (soleus), but is not expressed in fast skeletal muscle (extensor digitorum longus and anterior tibialis) or in neonatal or adult brain, kidney, lung, liver, or testis. In addition, while the cTnC gene is not expressed in murine C2C12 myoblasts, differentiation of these cells into myotubes was shown to result in a dramatic induction of cTnC gene expression. A full length cTnC genomic clone was isolated from a murine genomic library by hybridization with a cTnC cDNA probe and structurally characterized by DNA sequence, primer extension, and S1 nuclease protection analyses. The cTnC gene is 3.4 kilobase pairs long and is composed of six exons. The introns do not appear to divide the gene into functional domains. Analysis of the 5'-flanking region of the gene revealed the presence of a consensus TATA box 24 base pairs 5' of the transcription start site. Despite the finding that the gene is expressed only in cardiac and slow skeletal muscle, it lacks the previously described CArG and M-CAT transcriptional regulatory sequence motifs that are involved in regulating the expression of a number of other myofibrillar genes.
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PMID:Structure and expression of the murine slow/cardiac troponin C gene. 275 13

The beta-galactoside alpha-2,6-sialyltransferase represents a member of a family of sialyltransferases which catalyze the terminal addition of sialic acid to maturing carbohydrate chains. We surveyed rat tissues using cDNA probes complementary to coding and noncoding domains of the rat liver alpha-2,6-sialyltransferase. In addition to the expected differences in the level of sialyltransferase mRNA among the tissues, there were dramatic qualitative differences as well. Hepatic sialyltransferase probes hybridize to mRNAs of varying size on Northern blots. A tissue-dependent pattern of expression of these transcripts is documented. Evidence is presented that the multiple transcripts are generated from a common gene sequence. At least one instance of alternate splicing in the generation of the kidney sialyltransferase transcripts is predicted by S1 nuclease analysis. We report the isolation of a rat kidney cDNA clone, RKA, that substantiates this tissue-specific alternate splicing event. The RKA insert, although less than full-length, apparently encodes a polypeptide divergent from the reported hepatic alpha-2,6-sialyltransferase (1). RNA blot analysis indicates that the RKA-type transcripts represent a significant proportion of sialyltransferase RNA in rat kidney. Another class of kidney cDNA clones, RKE, is colinear with the hepatic sialyltransferase sequence. RNA blots probed for the divergent and common regions suggest that complex processing pathways are operative in the tissue-specific expression of sialyltransferase mRNA.
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PMID:Tissue-specific expression of beta-galactoside alpha-2,6-sialyltransferase. Transcript heterogeneity predicts a divergent polypeptide. 279 63

The DNA sequences of the Caulobacter crescentus trpF, trpB, and trpA genes were determined, along with 500 base pairs (bp) of 5'-flanking sequence and 320 bp of 3'-flanking sequence. An open reading frame, designated usg, occurs upstream of trpF and encodes a polypeptide of 89 amino acids which seems to be expressed in a coupled transcription-translation system. Interestingly, the usg polypeptide is not homologous to any known tryptophan biosynthetic enzyme. S1 nuclease mapping of in vivo transcripts indicated that usg, trpF, trpB, and trpA are arranged into a single operon, with the transcription initiation site located 30 bp upstream from the start of usg. Sequences centered at -30 and -6 bp upstream from the transcription initiation site are somewhat homologous to the Escherichia coli promoter consensus sequence and are homologous to sequences found upstream of genes from several organisms which are evolutionarily related to C. crescentus. Furthermore, the trpFBA operon promoter sequence lacks homology to promoter sequences identified for certain developmentally regulated C. crescentus genes. The structures of the C. crescentus usg, trpF, trpB, and trpA genes were further analyzed in terms of codon usage, G+C content, and genetic signals and were related to genetic signals previously identified in C. crescentus and other bacteria. Taken together, these results are relevant to the analysis of gene expression in C. crescentus and the study of trp gene structure and regulation.
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PMID:Structure of the Caulobacter crescentus trpFBA operon. 282 22

Transcription initiation of the hisA gene in vivo in the archaebacterium Methanococcus vannielii, as determined by nuclease S1 and primer extension analyses, occurs 73 base pairs (bp) upstream of the translation initiation site. Binding of M. vannielii RNA polymerase protects 43 bp of DNA, from 35 bp upstream (-35) to 8 bp downstream (+8) of the hisA mRNA initiation site, from digestion by DNase I and exonuclease III. An A + T rich region, with a sequence which conforms to the consensus sequence for promoters of stable RNA-encoding genes in methanogens, is found at the same location (-25) upstream of the polypeptide-encoding hisA gene. It appears therefore that a TATA-like sequence is also an element of promoters which direct transcription of polypeptide-encoding genes in this archaebacterium.
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PMID:An archaebacterial RNA polymerase binding site and transcription initiation of the hisA gene in Methanococcus vannielii. 282 15

Eubacterium sp. strain VPI 12708 is an anaerobic intestinal bacterium that has inducible bile acid 7-dehydroxylation activity. At least four new polypeptides were synthesized after addition of primary bile acids to the growth medium. One of these, of molecular weight 27,000 (P-27), was shown to be involved in the 7-dehydroxylation reaction sequence. The gene coding for P-27 was cloned, and the entire DNA sequence for the protein-coding region was determined. In addition, sequence information was obtained for 294 bases upstream from the translational start codon and 329 bases downstream from the stop codon. Induction studies with a synthetic oligonucleotide probe (16-mer) revealed the presence of a cholic acid-inducible mRNA species approximately 900 bases long. A 5' terminus of this mRNA was detected by primer extension analysis, and the location of the 3' terminus of the mRNA was estimated by using S1 nuclease mapping. The 3' terminus of the mRNA contained a large element with dyad symmetry of unknown function. The open reading frame contained 249 codons, and the corresponding polypeptide had a calculated molecular weight of 26,745. The amino acid sequence of P-27 showed significant homology to several previously described alcohol-polyol dehydrogenases ("nonzinc" dehydrogenases), especially in the region believed to contain a pyridine nucleotide-binding domain. The implications of this homology and the possible function of P-27 in bile acid 7-dehydroxylation are discussed.
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PMID:Nucleotide sequence and regulation of a gene involved in bile acid 7-dehydroxylation by Eubacterium sp. strain VPI 12708. 283 20

The physical positions of the DNA sequences encoding the five consecutive enzyme activities required to metabolise 3-deoxy-D-arabino-heptulosonic acid-7-phosphate to 5-enolpyruvyl-shikimate-3phosphate, which are encoded by the A. nidulans Arom polypeptide have been determined. Subfragments of the Arom locus encoding EPSP synthase and 3-dehydroquinase have been expressed in appropriate E. coli aro mutants. The DNA sequence of the A. nidulans Arom locus has been shown to have homology with the corresponding unlinked E. coli aro loci strongly suggesting (I) divergent evolution from common ancestral sequences and (II) that the complex A. nidulans Arom locus arose by multiple gene fusion. The DNA and protein sequence of the two 3-dehydroquinase isoenzymes of A. nidulans share no homology, strongly indicating separate phylogenetic origins and their convergent evolution. The 5' and 3' non-translated DNA sequence of the A. nidulans Arom locus is presented along with the presumed sites for transcription initiation and polyadenylation determined by S1 nuclease protection experiments.
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PMID:The complex Arom locus of Aspergillus nidulans. Evidence for multiple gene fusions and convergent evolution. 283 80

The gene encoding the precursor polypeptide of the Marek's disease herpesvirus (MDHV) secretory glycoprotein gp57-65 (formerly identified as A antigen) has been sequenced. Previous results had localized the gene to a 4.6-kilobase (kb) segment of the BamHI B fragment in the unique long region of the MDHV genome. S1 nuclease protection experiments were used to more precisely locate the 5' initiation and approximate 3' termination points of the approximately 1.8-kb MDHV gp57-65 mRNA within this segment. These results indicated that the entire MDHV gp57-65 coding sequence is contained within a 2.35-kb PvuII-EcoRI fragment, with the direction of transcription from PvuII to EcoRI (5' to 3'). Nucleotide sequence analysis of this region revealed a single open reading frame of 1,515 base pairs. The MDHV gp57-65 coding sequence has an overall guanosine-plus-cytosine content of 41%. Translation of the single open reading frame would produce a polypeptide of 505 amino acids, with a calculated molecular weight of 56,805. The putative gp57-65 precursor polypeptide contains features common to many glycoproteins. These include a hydrophobic amino-terminal region (amino acids 1 to 27) that may function as a signal peptide and nine potential N-linked glycosylation sites (Asn-X-Ser/Thr). These two features, predicted from nucleotide sequence data, are consistent with the published data showing that gp57-65 has a signal peptide and N-linked glycosylation (R. J. Isfort, R. A. Stringer, H.-J. Kung, and L. F. Velicer, J. Virol. 57:464-474, 1986). The predicted sequence indicates that overall the polypeptide is relatively hydrophobic, with a possible 18-residue carboxyl-terminal membrane anchor sequence. This sequence appears to be less prominent than those commonly found in integral membrane glycoproteins. The lack of a strong hydrophobic anchor sequence may help to explain the predominantly secretory nature of MDHV gp57-65.
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PMID:Structure and complete nucleotide sequence of the Marek's disease herpesvirus gp57-65 gene. 283 20

Previous observations demonstrated that a lethal variant of osteogenesis imperfecta had two altered alleles for pro alpha 2(I) chains of type I procollagen. One mutation produced a nonfunctioning allele in that there was synthesis of mRNA but no detectable synthesis of pro alpha 2(I) chains from the allele. The mutation in the other allele caused synthesis of shortened pro alpha 2(I) chains that lacked most or all of the 18 amino acids encoded by exon 28. Subclones of the pro alpha 2(I) gene were prepared from the proband's DNA and the DNA sequence was determined for a 582-base-pair (bp) region that extended from the last 30 bp of intervening sequence 26 to the first 26 bp of intervening sequence 29. Data from six independent subclones demonstrated that all had the same sequence as a previously isolated normal clone for the pro alpha 2(I) gene except that four subclones had a single base mutation at the 3' end of intervening sequence 27. The mutation was a substitution of guanine for adenine that changed the universal consensus sequence for the 3' splicing site of RNA from -AG- to -GG-. S1 nuclease experiments demonstrated that about half the pro alpha 2(I) mRNA in the proband's fibroblasts was abnormally spliced and that the major species of abnormal pro alpha 2(I) mRNA was completely spliced from the last codon of exon 27 to the first codon of exon 29. The mutation is apparently unique among RNA splicing mutations of mammalian systems in producing a shortened polypeptide chain that is in-frame in terms of coding sequences, that is used in the subunit assembly of a protein, and that contributes to a lethal phenotype.
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PMID:Single base mutation in the pro alpha 2(I) collagen gene that causes efficient splicing of RNA from exon 27 to exon 29 and synthesis of a shortened but in-frame pro alpha 2(I) chain. 283 39


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