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 major neuronal populations of the primate cerebral cortex can be classified immunocytochemically according to their transmitters and in terms of the differential expression of certain other molecules such as neuropeptides, calcium-binding proteins and protein kinases. We have been able to chart the time course of developmental expression of these molecules and to show that gene expression for many of them is regulated in adult and infant animals by afferent activity entering the cortex. In the visual cortex of adult monkeys, levels of immunocytochemically detectable gamma aminobutyric acid (GABA), of its synthesizing enzyme glutamic acid decarboxylase (GAD) and of the tachykinins are greatly reduced in deprived ocular dominance columns within 24 h of blocking impulse activity in the optic nerve by intraocular injection of tetrodotoxin (TTX). Conversely, levels of immunocytochemically detectable calcium-calmodulin-dependent protein kinase (CAMII kinase) are increased in deprived eye dominance columns. These effects are quickly reversible on restoration of binocular vision, and experiments involving in situ hybridization and S1 nuclease protection assays show that the changes are associated with parallel changes in mRNA levels for preprotachykinin and CAM II kinase, but not for GAD, which appears to be regulated by post-transcriptional mechanisms. Experiments in the primate somatic sensory cortex suggest comparable activity-dependent effects on gene expression there also. It is proposed that effects of this type underlie the establishment of cortical maps during development and their activity-dependent mutability in adulthood.
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PMID:The role of afferent activity in the maintenance of primate neocorticalfunction. 217 67

A region of the Reticuloendotheliosis virus (REV) long terminal repeat (LTR) harbouring single or duplicated copies of 46-bp and 26-bp sequence elements is implicated in enhancer activity. Sequences residing upstream from the proviral 3' LTR did not contribute to activity of the intact LTR. Gene expression regulated by a combination of REV enhancer and SV40 early region promoter was 50-fold less than from the analogous construct containing the chicken syncytial virus promoter. Deletion of LTR sequences immediately downstream of the CAP site, which include a region capable of forming a stable hairpin in the mRNA, decreased expression by 70%. Expression assays and S1 nuclease mapping showed that a second transcriptional start site, identified by transcription in vitro using HeLa cell lysates and purified DNA templates, was not used in vivo in the cell lines examined.
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PMID:Transient expression analysis of the reticuloendotheliosis virus long terminal repeat element. 254 93

Three direct repeats of 320, 340 and 238 nucleotides were detected upstream to the 5' end of the 18S rRNA gene of an rDNA unit present on a 9.8 kb EcoRI fragment of the rice DNA. The primer extension analysis showed that the site of initiation of transcription is in the 1st repeat at an A, the 623rd nucleotide upstream to the 5' end of the 18S rRNA gene. Different stretches of the intergenic spacer DNA linked to the Chloramphenicol acetyl transferase gene were transcribed in the intact nuclei of rice embryos. The S1 nuclease protection analysis of the transcripts using [32P]-labelled Chloramphenicol acetyl transferase gene as the probe showed the presence of multiple promoters for rDNA transcription.
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PMID:Initiation of transcription of rDNA in rice. 254 87

In this report, we determined that induction of the DR alpha-chain by recombinant human interferon-gamma (IFN-gamma) in a human glioblastoma multiform cell line is transcriptionally regulated and showed that protein synthesis is not necessary for this to occur. The regions of the DR alpha-chain gene that are responsible for basal and recombinant IFN-gamma-induced gene transcription have been determined by gene transfer of a series of 5' deletion mutants in which the upstream region of the DR alpha chain was linked to a reporter gene, chloramphenicol acetyltransferase. Chloramphenicol acetyltransferase transcript and protein levels were determined by S1 nuclease protection and chloramphenicol acetyltransferase enzyme assays, respectively. By using these deletion mutants, we were able to draw the following conclusions. (i) One hundred and nine base pairs of upstream sequence contains the basic DR alpha-chain gene promoter and represents the minimal amount of sequence necessary for basal gene expression. (ii) An additional 9 base pairs of upstream sequence can mediate recombinant IFN-gamma induction. (iii) Maximal recombinant IFN-gamma induction requires at most an additional 23 base pairs of upstream sequence. (iv) The sequence between positions -267 and -141 does not appear to contain any additional positive or negative regulatory elements. These results suggest that the region between positions -141 and -109 contains a critical IFN-gamma-responsive element. Substitution mutagenesis was performed to confirm this suggestion.
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PMID:Detailed delineation of an interferon-gamma-responsive element important in human HLA-DRA gene expression in a glioblastoma multiform line. 284 68

A series of recombinant plasmid vectors containing hepatitis B virus (HBV) DNA sequences was constructed to study the biosynthesis of the hepatitis B virus surface antigen (HBsAg) RNA and to locate transcriptional control elements involved in the regulation of the S and pre-S DNA sequences. We examined the transcription of the HBsAg gene in permanent cell lines that were developed by transfecting with recombinant vectors containing HBV sequences and the neomycin gene followed by G418 selection. We further defined the promoter activities upstream of and within the pre-S sequences using the assayable chloramphenicol acetyltransferase gene. Results obtained from S1 nuclease digestion and primer extension suggest that HBsAg transcripts are initiated at multiple sites in the pre-S region and from a site upstream of the pre-S region. Chloramphenicol acetyltransferase assays indicate that DNA sequences within and upstream of the pre-S region contain promoter activities and that the "TATA" sequence-containing promoter and the internal promoter show similar levels of activities in CV-1 cells and several other cell lines tested.
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PMID:Transcriptional control elements of hepatitis B surface antigen gene. 345 53

S1 nuclease was used to generate a series of deletions which extend into the CAP-cAMP binding site from upstream of the Escherichia coli lactose operon promoter (lacP). Deletion and insertion mutations were also created which changed the spacing region between the CAP-cAMP binding site and the lacP -35 region. The promoter activities of these mutations were compared by measuring the levels of beta-galactosidase gene expression in vivo. The results show that sequence information prior to 74 base pairs (-74) upstream from the transcription start site (designated as +1) is not necessary for the full activation of the lac promoter by the CAP-cAMP complex. However, the deletion which extends to the -71 position retains only one third of the promoter activity in the presence of the CAP-cAMP complex. Removal of one symmetrical element from the two fold symmetry in the CAP-cAMP binding site abolished the CAP-cAMP stimulation of the lac promoter. Spacer mutations which increase by one base pair or decrease by two base pairs the length of the spacing region between the CAP-cAMP binding site and the lacP -35 region drastically reduced the CAP-cAMP stimulation of the lac promoter. This suggests that the distance between the lac promoter transcription start site and CAP-cAMP binding site is crucial for the function of the lac promoter, despite the fact that this distance varies in other E. coli promoters positively regulated by CAP-cAMP. A deletion which extends to the -59 position results in a two fold enhanced expression of lac in the absence of CAP-cAMP. This is consistent with the existance of a competitive RNA polymerase binding site in this region which would normally act to inhibit RNA polymerase binding.
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PMID:Deletion analysis of the CAP-cAMP binding site of the Escherichia coli lactose promoter. 608 87

We have attempted to investigate the conformational basis and developmental relevance of globin-associated hypersensitive sites in avian and human cells. Our results indicate that once formed, DNaseI-hypersensitive sites have the capacity to propagate their own structure to daughter cells in the absence of the original events that have led to their formation. We postulate that the single-stranded character (as revealed by S1 nuclease) of these DNaseI-hypersensitivity sites could explain these results. In addition, we show that the locations of hypersensitive sites in an active avian endogenous retrovirus remain unmethylated in mature sperm and suggest that this phenomenon could lead to the propagation of structural information from germ line to fertilized egg. We have also investigated the chromatin structure of the chromosomal DNA regions containing the human G gamma-, A gamma-, delta-, and beta-globin structural genes in both fetal and adult erythropoietic tissues. Our results indicate that DNaseI introduces specific cuts into the beta-globin gene cluster in erythroid cells, but not in white blood cells. The predominant sites are located at the 5' sides of the G gamma-, A gamma-, delta-, and beta-globin genes, within 200 bp of the respective CAP sites. Examination of fetal liver cells has revealed the presence of hypersensitive sites at the 5' side of all four genes, whereas analysis of adult bone marrow has revealed the characteristic sites near the delta- and beta-globin genes but no hypersensitive sites at the 5' termini of the G gamma- or A gamma-globin genes. The presence of delta- and beta-hypersensitive sites in fetal cells suggests that the increment in expression of the delta and beta genes during development most likely involves the modulation of another pathway to gene expression.
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PMID:Developmental aspects of chromatin structure and gene expression. 619 53

Intracytoplasmic A particles (CAP), previously identified as probably cytoplasmic nucleocapsid precursor structures to mouse mammary tumour virus (MMTV), possess both DNA binding and DNA unwinding activities, CAP proteins bind to both single-stranded (ss)- and double-stranded (ds)DNA, with the ssDNA slightly preferred. This activity was linear over a 30-fold concentration of A particle protein and was not affected by NaCl concentrations as high as 0.6 M or pH changes over a wide range. DNA binding by CAP proteins was sensitive to heat or addition of sodium dodecyl sulphate (SDS) and was neutralized by pre-incubation of CAP with anti-MMTV p14, but not by anti-MMTV p27, p10 or anti-mouse casein. Incubation of CAP with dsDNA led to unwinding of the double helix as measured by its increased sensitivity to S1 nuclease digestion. This activity was also linear over a several-fold concentration of A particle protein and was heat labile. It was not inhibited by pre-incubation of CAP with either anti-MMTV p14 or with anti-MMTV, anti-MMTV p27 and anti-MMTV p10. DNA unwinding was inhibited by anti-A particle antiserum and to a lesser extent by anti-CAP p20-18.
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PMID:DNA binding and unwinding activities associated with intracytoplasmic a particles isolated from mouse mammary tumors. 625 67

A family of plasmids containing short pieces of Escherichia coli lac promoter DNA has been constructed. DNA fragments from any source may be inserted directly into the unique EcoRI sites of some of these plasmids to achieve transcription under the control of the lacUV5 promoter. Alternatively, the plasmids serve as convenient sources of lac DNA fragments ('portable promoters') containing the 'up' promoter mutations UV5 or Ps (super promoter) as well as the wild-type promoter. pOP95-2, pOP95-5, pOP203-1, pOP203-2 and pOP203-3 are derivatives of pMB9 while pOP95-15 and pOP203-13 are derivatives of pBR322. The pOP95 plasmids contain the 95-bp AluI lac fragment. This fragment includes the UV5 promoter (minus the CAP binding site), the repressor binding site, and ends 2 bp before an ATG encoding the beta-Gal start codon. The pOP203 plasmids contain the 203-bp HaeIII lac fragment. This fragment contains the UV5 promoter (including the L8 mutation in the CAP binding site), the repressor binding site and sequences encoding the first 8 amino acids of beta-Gal. To shorten and introduce reading frame heterogeneity in the beta-Gal coding end of the pOP203 plasmids, the EcoRI site in pOP203-12 was moved upstream by digesting EcoRI cut plasmid DNA with T4 DNA polymerase and S1 nuclease followed by ligation in the presence of EcoRI linker. This produced the plasmids pOP203-24, pOP203-27, pOP203-28 and pOP203-29. pOP203-29 encodes essentially just that portion of the beta-Gal mRNA sequence which is protected from nuclease digestion by the bound ribosomal complex (Maizels, 1974).
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PMID:A family of cloning vectors containing the lacUV5 promoter. 629 48

We have investigated the sites sensitive to the S1 nuclease which are presented in a supercoiled plasmid, pSVS 3.3. This plasmid contains the entire transcription unit plus 5'- and 3'-flanking regions of the rat seminal vesicle IV gene on a 3.3 kb Eco RI fragment (Harris et al., 1983). Using a cDNA probe of rat seminal vesicle secretion product IV (SVS IV) mRNA, we have demonstrated S1 nuclease-sensitive sites in the 5'-flanking and in the 3'-flanking regions of SVS IV gene. The site in the 5'flanking region has been mapped to approximately 117 bp upstream from the CAP site. This site at -117 bp can potentially form a cruciform structure as inferred from the presence of inverted repeats in this region (Lilley, 1981; Panayotatos and Wells, 1981). We have now shown such a structure most probably exists. The S1 nuclease-sensitive site in the 3'flanking region is present in an area of highly repeated sequence.
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PMID:The seminal vesicle secretion IV gene: detection of S1 nuclease-sensitive sites in supercoiled plasmid pSVS 3.3. 630 19


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