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 identities of two cloned, arabinose-inducible promoters were tested by hybridizing promoter DNA fragments with restriction digests of chromosomal DNA containing Mudlac phage inserted in either araFGH or in araE transport operons. One promoter, thought to be araE, is within 10(3) base-pairs of a Mudlac insertion in the araE gene. The second promoter was not found within several thousand base-pairs of either of the known transport genes. This promoter is now named araPJ (araJ). The DNA sequence of the fragment containing the araFGH promoter was determined. The start site of transcription in vivo was located to within +/- 1 base-pair (bp) by S1 nuclease mapping. DNase 1 footprinting revealed that, in comparison with the araBAD and araE promoters, the locations of the AraC and cyclic AMP receptor protein (CRP) binding sites are reversed with CRP lying between AraC and RNA polymerase. The central location of the CRP binding site may explain why the araFGH promoter is more catabolite sensitive than the other ara promoters. AraC and CRP were both required for maximal transcription in vitro, although a low level of transcription was detected with CRP alone. S1 nuclease mapping of mRNA-DNA hybrids from the araJ promoter located the transcription start point to within #/- 3 bp, and demonstrates that the promoter is dependent upon AraC protein and CRP in vivo. DNase footprinting showed that the location of the AraC protein binding site on araJ is adjacent to the RNA polymerase site, as seen at the araBAD and araE promoters. Two CRP sites were observed; one is upstream from the AraC site and one is downstream from the transcription start site.
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PMID:Characterization of the Escherichia coli araFGH and araJ promoters. 223 17

The initiation sites of transcription in vivo for the three genes caa, cai and cal encoding respectively colicin A (Caa), the immunity protein (Cai) and the pColA lysis protein (Cal) have been analysed by nuclease S1 mapping. This analysis demonstrates that caa and cal form an operon. cai is located between these two genes and transcribed in the opposite direction from its own promoter. The start sites for caa and cai have also been determined in vitro. For caa, the same start site was found in vivo and in vitro. In contrast, for cai the most efficient start site in vitro was not used in vivo. LexA protein strongly repressed the in vivo and in vitro transcription of the caa-cal operon. As determined by DNase 1 protection experiments, LexA protein binds with a high affinity to an approximately 40 bp long sequence just downstream of the Pribnow box. The sequence of the binding site is composed of two overlapped "SOS boxes". Two transcripts of the caa-cal operon were detected by blot hybridization. The longer mRNA can direct the synthesis of both Caa and Cal while the shorter one is terminated at the end of caa. When the transcription of the caa-cal operon is induced, there is a strong interference with cai transcription.
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PMID:The promoters of the genes for colicin production, release and immunity in the ColA plasmid: effects of convergent transcription and Lex A protein. 242 Dec 51

In a simple eukaryote Physarum polycephalum about 13% of the genome is transcribed into abundant cytoplasmic RNA as shown by S1 nuclease digestion of DNA-RNA hybrids. Mild digestion of isolated Physarum nuclei with DNase I liberates a fraction of chromatin 3.5-fold enriched in sequences hybridizing by Physarum poly(A)+ RNA. This fraction is similarly enriched in histone H4 and actin genes known to be actively transcribed in Physarum. High content (about 45%) of actively transcribed sequences in DNase-I-released fraction of Physarum chromatin makes it particularly well suited for studying the structural basis of transcriptional activation in eukaryotes.
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PMID:Transcriptionally active chromatin can be selectively released by DNase I from Physarum polycephalum genome. 246 74

Total RNA from Ehrlich ascites mitochondria pretreated with RNase-free DNase was capped in vitro with [alpha-32P]GTP and guanylyl transferase. The cappable RNAs representing the primary transcripts show a heterogeneous size distribution with four major species of 46, 63, 94, and 152 nucleotides and four minor species of 19, 24, 104, and 790 nucleotides in size. Hybridization with the D-loop DNA probes shows that the 19-nucleotide-long capped RNA is coded by the H-strand of mitochondrial DNA while the rest are coded by the L-strand. S1 nuclease mapping and primer extension analyses suggest the occurrence of a transcription initiation of H-strand at about 19 nucleotides upstream from the start of the tRNA(Phe) gene. All of the L-strand cappable RNAs have a common 5' end mapping to nucleotide 16,183 +/- 5 of the genome. The 3' ends of four major cappable RNA species line up to the conserved sequence boxes, putative start sites of DH-DNA; and in fact about 2% of these cappable species are found to exist as DNA-linked RNA under steady-state conditions. The 3' end of the 790-nucleotide cappable RNA lies close to the start of the tRNA(Pro) gene, suggesting that it may be the true precursor of L-strand transcript endonucleolytically processed at the 3' end. The level of L-strand-coded cappable RNAs varies markedly under different growth conditions. Treatment with cycloheximide results in a reduction while chloramphenicol caused over 3-fold induction, suggesting that these "primer" RNAs may have an additional regulatory function.
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PMID:Characterization of primary transcripts and identification of transcription initiation sites on the heavy and light strands of mouse mitochondrial DNA. 271 42

The nucleic acid of chicken parvovirus-like particles showed sensitivity to DNase and S1 nuclease treatment and resistance to digestion with RNase. Viral DNA readily served as a template for self-primed conversion in vitro into a double-stranded form of about 5200 base pairs. There was no evidence for encapsidation of strands of opposite polarities. These findings confirm the taxonomic classification of chicken parvovirus-like particles as fowl parvovirus type 1 within the Parvovirus genus of the Parvoviridae.
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PMID:The genome structure of a new chicken virus identifies it as a parvovirus. 299 61

Nucleases derived from Neurospora crassa mycelia with neutral single-strand (ss) endodeoxyribonuclease activity have been examined by immunochemical techniques and by sodium dodecyl sulfate - DNA gel electrophoresis. All of the intracellular nucleases, which have different divalent metal ion requirements, different strand specificities with single- and double-strand DNA, different modes of action on DNA and RNA, and other distinguishing characteristics, are immunochemically related to Neurospora endo-exonuclease. The evidence indicates that these enzymes are derived from one or more related large, inactive (precursor?) polypeptides that are first converted to 75- to 80-kdalton active polypeptide(s) which are very protease sensitive. Further limited proteolysis results in the production of the various active forms of nuclease studied here. Some proteolytic conversions may occur in a controlled manner in vivo in different cell compartments, but others are very likely artifacts resulting from uncontrolled proteolysis during extraction and isolation. The intracellular forms of Neurospora endo-exonuclease are immunologically cross-active with ss-DNA-binding nucleases isolated from Aspergillus nidulans and Saccharomyces cerevisiae. They are not immunochemically related to two extracellular Neurospora nucleases, the pancreatic DNase-I-like DNase A and a ss-specific exonuclease, and they are also not related to other fungal and plant nucleases with ss-specific endonuclease activity such as the S1 nuclease of Aspergillus oryzae, the P1 nuclease of Penicillium citrinum, and mung bean nuclease.
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PMID:An immunochemical study of Neurospora nucleases. 301 42

Mouse L-cell nucleoli were isolated from sonicated nuclei by centrifugation and extensively treated with pancreatic DNase or micrococcal nuclease to obtain "core nucleoli." Core nucleoli still contained the precursors to rRNA and about 1% of the total nuclear DNA, which remained tightly bound even after the removal of some chromatin proteins with 2 M NaCl. The core nucleolar DNA electrophoresed in a series of discrete bands, 20 to about 200 base pairs in length. Hybridization tests with specific DNA probes showed that the DNA was devoid of sequences complementary to mouse satellite, mouse Alu-like, and 5S RNA sequences. It also lacked sequences coding for cytoplasmic rRNA species, since it did not hybridize to the 18S to 28S portion of rDNA in Northern blot analyses and none of it was protected by hybridization to a 100-fold excess of total cytoplasmic RNA in S1 nuclease assays. However, the core nucleolar DNA did hybridize to nontranscribed and external transcribed spacer rDNA sequences. We infer that specific portions of rDNA are protected from DNase action by a tight association with nucleolar structural proteins.
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PMID:Localization of specific rDNA spacer sequences to the mouse L-cell nucleolar matrix. 403 54

We sequenced the 274-nucleotide intercistronic glnA-glnL region of Escherichia coli to localize regulatory regions postulated from genetic evidence. The transcriptional start of glnLp, identified by S1 nuclease mapping, preceded the structural gene by 32 bases. NR1, the glnG gene product and a repressor of glnLp, protected from DNase digestion a region of DNA between -12 and +15 from the transcriptional start. A mutation rendering glnLp insensitive to NRI was within the protected region in a-TGCA- sequence found in all nitrogen-regulated operons, providing evidence for involvement of this sequence in interactions with NRI. We also observed in the intercistronic region a potential rho-independent terminator preceding glnLp and a sequence previously found in other intercistronic regions.
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PMID:Identification and regulation of the glnL operator-promoter of the complex glnALG operon of Escherichia coli. 614 34

Reaction intermediates formed during the degradation of linear PM2, T5, and lambda DNA by herpes simplex virus (HSV) DNase have been examined by agarose gel electrophoresis. Digestion of T5 DNA by HSV type 2 (HSV-2) DNase in the presence of Mn(2+) (endonuclease only) gave rise to 6 major and 12 minor fragments. Some of the fragments produced correspond to those observed after cleavage of T5 DNA by the single-strand-specific S1 nuclease, indicating that the HSV DNase rapidly cleaves opposite a nick or gap in a duplex DNA molecule. In contrast, HSV DNase did not produce distinct fragments upon digestion of linear PM2 or lambda DNA, which do not contain nicks. In the presence of Mg(2+), when both endonuclease and exonuclease activities of the HSV DNase occur, most of the same distinct fragments from digestion of T5 DNA were observed. However, these fragments were then further degraded preferentially from the ends, presumably by the action of the exonuclease activity. Unit-length lambda DNA, EcoRI restriction fragments of lambda DNA, and linear PM2 DNA were also degraded from the ends by HSV DNase in the same manner. Previous studies have suggested that the HSV exonuclease degrades in the 3' --> 5' direction. If this is correct, and since only 5'-monophosphate nucleosides are produced, then HSV DNase should "activate" DNA for DNA polymerase. However, unlike pancreatic DNase I, neither HSV-1 nor HSV-2 DNase, in the presence of Mg(2+) or Mn(2+), activated calf thymus DNA for HSV DNA polymerase. This suggests that HSV DNase degrades both strands of a linear double-stranded DNA molecule from the same end at about the same rate. That is, HSV DNase is apparently capable of degrading DNA strands in the 3' --> 5' direction as well as in the 5' --> 3' direction, yielding progressively smaller double-stranded molecules with flush ends. Except with minor differences, HSV-1 and HSV-2 DNases act in a similar manner.
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PMID:Mechanism of degradation of duplex DNA by the DNase induced by herpes simplex virus. 626 48

The adenovirus-specific DNA-binding protein (DBP) has been shown to inhibit the hydrolysis of single-stranded DNA by a DNase isolated from KB cells, (Nass, K., and Frenkel, G.D. (1980). J. Virol. 35, 314-319). The specificity of the inhibition has now been investigated. The DBP inhibits the hydrolysis of single-stranded DNA by several different DNases (DNase II, KB DNase, S1 nuclease) under a variety of reaction conditions, but it has no effect on DNase I-catalyzed hydrolysis of single-stranded DNA. The DBP also inhibits the rate of hydrolysis of double-stranded DNA by KB DNase and DNase II, but has no effect on DNase I-catalyzed hydrolysis of this substrate. The DBP also inhibits the dephosphorylation of 5'-phosphoryl-terminated DNA by bacterial alkaline phosphatase but stimulates the phosphorylation of 5'-hydroxyl-terminated DNA by polynucleotide kinase.
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PMID:DNase inhibition by the adenovirus DNA-binding protein exhibits specificity for the enzyme but not for the secondary structure of the DNA. 630 53


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