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)

Transcription of the platelet-derived growth factor (PDGF) A-chain gene is activated in cells exposed to growth factors. We now have identified a homopurine/homopyrimidine domain in the promoter region of the PDGF A-chain gene that exhibits S1 nuclease sensitivity in vitro and that contains a novel binding site (5'-TCCTCCTCCTCCTC-3') for the growth factor inducible transcription factor EGR-1 as demonstrated in gel mobility shift assays. Sequences similar to this novel EGR-1 binding site were observed also in five growth-related genes and shown to bind to EGR-1 in competition assays, suggesting that EGR-1 may influence the transcriptional regulation of these growth-related genes.
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PMID:An S1 nuclease-sensitive homopurine/homopyrimidine domain in the PDGF A-chain promoter contains a novel binding site for the growth factor-inducible protein EGR-1. 141 65

Homodimers of the platelet-derived growth factor (PDGF) A-chain are strong mitogens for cells of mesenchymal origin. Differences in the levels of expression of the PDGF A-chain gene have been reported in both normal and transformed cell lines, suggesting that transcription of the PDGF A-chain gene is highly regulated. We have now identified two S1-hypersensitive sites which flank a 13-base pair oligo(dG).oligo(dC) sequence located 70-82 base pairs upstream of the transcription initiation site. Three lines of evidence suggest that these S1-sensitive sites contribute to optimum promoter activity. Nuclear protein(s) binding to these sites were detected in gel mobility shift assays. Deletion of the S1-sensitive sites results in a 2-3-fold decrease in the transcriptional activity and eliminated sensitivity to S1 nuclease. Deletions in the oligo(dG).oligo(dC) motif also eliminated sensitivity to S1 and resulted in a 2.5-fold decrease of the promoter activity in the stable transfection assays. The results suggest that the highly G+C-rich region in the PDGF A-chain gene promoter locally induces the formation of non-B-form DNA under torsional stress which appears to be important in the transcriptional regulation of the PDGF A-chain gene in vivo.
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PMID:Modulation of transcription of the platelet-derived growth factor A-chain gene by a promoter region sensitive to S1 nuclease. 151 41

Levels of expression of the platelet-derived growth factor (PDGF) A-chain gene differ significantly in normal and transformed cells. We have identified an S1 nuclease-sensitive site in a GC box located at -55 to -72 in the PDGF A-chain promoter region. We now demonstrate that a 24-base, G-rich complementary oligonucleotide anneals specifically to the C-rich strand of the GC box and protects the GC box from nicking by S1 nuclease whereas the C-rich complementary oligonucleotide and its double-stranded counterpart do not. In transient transfection assays, expression of the PDGF A-chain gene is sharply reduced by deletions within the GC box or if the 24-base G-rich complementary oligonucleotide is preincubated with the promoter construct prior to transfection. The data suggest that the GC box of the PDGF A-chain gene may promote a non-B-form DNA structure, which is recognized by S1 nuclease and which anneals to a short complementary G-rich oligonucleotide. The data also suggest that this non-B-form DNA is important for efficient transcription of PDGF A-chain gene.
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PMID:Binding of single-stranded oligonucleotides to a non-B-form DNA structure results in loss of promoter activity of the platelet-derived growth factor A-chain gene. 161 66

The platelet-derived growth factor (PDGF) A- and B-chain genes are widely expressed in mammalian tissues and their homodimeric gene products appear to regulate the autocrine growth of both normal and transformed cells. In this study, we analyzed the 5' flanking sequences of the human PDGF A-chain gene to seek elements important to regulating its transcription. The promoter region was exceptionally G + C-rich and contained a "TATA box" but no "CAAT box." The transcription start site was identified 845 base pairs 5' to the translation initiation site by S1 nuclease mapping and by primer extension. Both in vitro transcription and transient expression of the chloramphenicol acetyltransferase gene linked to the PDGF A-chain 5' flanking sequences established that the putative promoter region was active, and RNase H mapping established that the three characteristic mRNAs (1.9, 2.3, and 2.8 kilobases) used the same transcription start site, which was used in normal endothelial cells and in two human tumor cell lines that express high levels of A-chain transcripts. The results established an exceptionally G + C-rich promoter region and a single transcription start site active for each of the three mRNAs of the PDGF A-chain gene. DNA sites of potential importance in mediating the activation of the PDGF A-chain gene in normal cells and in transformed cell lines expressing high levels of PDGF A chain were identified.
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PMID:Promoter region of the human platelet-derived growth factor A-chain gene. 184 7

The platelet-derived growth factor (PDGF) A-chain gene is expressed in a tissue- and developmental stage-specific manner. Here we identify an S1 nuclease sensitive region within the first intron that functions as a negative regulatory element in HeLa but not in human glioblastoma (A172) cells in transient transfection assays. A 147 bp DNA fragment that contains this element functions in a position and orientation independent manner to negatively regulate both the PDGF A-chain promoter and the heterologous herpes simplex virus thymidine kinase (TK) promoter. The cell-type specific effect of this 147 bp DNA fragment is seen when it is located downstream but not upstream of the reporter gene driven by either the PDGF A-chain or TK promoters. The negative regulatory element has been localized to a 24 bp DNA sequence within the S1 sensitive site that retains negative regulatory activity and recognizes a nuclear protein in HeLa but not in A172 cells. Furthermore, the 24 bp element functions as a cell type-specific negative element independent of its position. These results suggest that a functional silencer within the first intron exhibits a non-B-form DNA structure under superhelical stress in vitro and may contribute to the cell type-specific transcriptional regulation of PDGF A-chain gene in vivo.
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PMID:An S1 nuclease-sensitive region in the first intron of human platelet-derived growth factor A-chain gene contains a negatively acting cell type-specific regulatory element. 812 85

Homodimers of the platelet-derived growth factor (PDGF) A-chain are strong mitogens for cells of mesenchymal origin and appear to be functionally important during development and perhaps in phenotypic transformation. In order to understand mechanisms of the developmental regulation of the PDGF A-chain gene and its dysregulation in transformation, we used S1 nuclease to identify and map an S1 hypersensitive region that is located 482 to 513 base pairs upstream of the transcription initiation site of the PDGF A-chain gene. A single nuclear protein binds to this site in gel mobility shift assays. This site confers a 2-3 fold increase in transcriptional activity when inserted into a heterologous promoter and analysed in transient transfection assays. The results suggest that this region of DNA under torsional stress locally assumes a single stranded character and functions to upregulate promoter activity.
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PMID:An S1 nuclease sensitive region in the PDGFA-chain gene promoter contains a positive transcriptional regulatory element. 829 11

We previously observed that transcription of the platelet-derived growth factor (PDGF) A-chain gene is enhanced in cells stimulated by PDGF through a serum response element (SRE) in its 5'-flanking sequence. We now show that the region of the SRE is sensitive to S1 nuclease in vitro. We also identify a single-stranded DNA-binding protein in HeLa cell nuclear extracts that binds to the noncoding strand of the PDGF A-chain SRE but not to its double-stranded counterpart or to the single-stranded coding sequence. Competition assays using oligonucleotides with sequence-specific mutations that diminished or eliminated detectable complex formation were used to establish the specificity of this protein/DNA interaction. Remarkably, the sequence-specific single-stranded binding protein binds to this region only when it is highly supercoiled. The data suggest that the single-stranded DNA-binding protein specifically interacts with a highly supercoiled region of the PDGF A-chain promoter and that this interaction may have a role in the transcriptional regulation of this gene.
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PMID:Identification of a single-stranded DNA-binding protein that interacts with an S1 nuclease-sensitive region in the platelet-derived growth factor A-chain gene promoter. 848 17

Spontaneously hypertensive rats (SHR)-derived vascular smooth muscle cells show exaggerated growth and increased expression of platelet-derived growth factor (PDGF) A-chain mRNA. We examined the effect of methylene methylimino linkage of antisense oligodeoxynucleotide, a novel modification of antisense oligodeoxynucleotide designed to increase nuclease resistance, to PDGF A-chain on the exaggerated growth of vascular smooth muscle cells from SHR. Methylene methylimino-linked oligodeoxynucleotide provided complete resistance against S1 nuclease. Methylene methylimino linkage of antisense oligodeoxynucleotide to PDGF A-chain resulted in a rapid inhibition of basal DNA synthesis of vascular smooth muscle cells from SHR. This inhibition was much greater than that produced by phosphorothioate linkage of antisense oligodeoxynucleotide to PDGF A-chain. The methylene methylimino linkage of antisense oligodeoxynucleotide to PDGF A-chain may prove useful in the treatment of arterial proliferative diseases including hypertension.
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PMID:Effect of methylene methylimino linkage of antisense oligonucleotide to the platelet-derived growth factor A-chain on growth of vascular smooth muscle cells from spontaneously hypertensive rats. 1076 64

The platelet-derived growth factor (PDGF)-A promoter is regulated by a number of GC-rich regulatory elements that possess non-B-form DNA structures. Screening of a HeLa cDNA expression library with the C-rich strand of a PDGF-A silencer sequence (5'-S1 nuclease-hypersensitive site (SHS)) yielded three cDNA clones encoding NM23-H1, a protein implicated as a suppressor of metastasis in melanoma and breast carcinoma. Recombinant human NM23-H1 cleaved within the 3'-portions of both 5'-SHS strands in either single-stranded or duplex forms. In contrast, NM23-H2, known as a transcriptional activator with a DNA cleavage function, cleaved within the 5'-portions of both strands, revealing that NM23-H1 and NM23-H2 cleave at distinct sites of the 5'-SHS and by different mechanisms. NM23-H1 and NM23-H2 also cleaved within the PDGF-A basal promoter region, again exhibiting preferences for cleavage within the 5'- and 3'-portions of the element, respectively. Transient transfection analyses in HepG2 cells revealed that both NM23-H1 and -H2 repressed transcriptional activity driven by the PDGF-A basal promoter (-82 to +8). Activity of the negative regulatory region (-1853 to -883), which contains the 5'-SHS, was also inhibited modestly by NM23-H1 and NM23-H2. These studies demonstrate for the first time that NM23-H1 interacts both structurally and functionally with DNA. They also indicate a role for NM23 proteins in repressing transcription of a growth factor oncogene, providing a possible molecular mechanism to explain their metastasis-suppressing effects.
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PMID:NM23-H1 and NM23-H2 repress transcriptional activities of nuclease-hypersensitive elements in the platelet-derived growth factor-A promoter. 1169 15

Apolipoprotein E (apoE) isoforms are key determinants of susceptibility to late-onset Alzheimer's disease (AD). The epsilon 4 and epsilon 2 alleles have been associated with increased and decreased risk for AD, respectively. We have generated and characterized transgenic mice in which the human apoE2 gene is expressed under the control of the platelet-derived growth factor B-chain (PDGF-B) promoter, or the transferrin (TF) promoter. S1 nuclease analysis and immunoblotting showed that the PDGF-B apoE2 mice express apoE2 exclusively in the brain whereas the TF apoE2 mice express apoE2 in the liver and in the brain. In the TF apoE2 mouse line, apoE2 is also detected in the plasma. The PDGF-B apoE2 and the TF apoE2 transgenic mice were bred back to apoE(-)(/)(-) background. Immunohistochemical analysis showed that the PDGF apoE2 x apoE(-)(/)(-) and the TF apoE2 x apoE(-)(/)(-) mice express human apoE2 within the neocortex in hippocampal neurons and glial cells, respectively. ApoE(-)(/)(-) mice have been shown to develop age-dependent loss of synaptophysin. Immunoblotting of mouse brain extracts and immunohistochemical analysis of brain sections showed that apoE expression in both apoE2 x apoE(-)(/)(-) transgenic lines was associated with significant recovery of brain synaptophysin levels as compared to the levels of apoE(-)(/)(-) littermates of the same age. These apoE2-expressing mice, when bred back on amyloid precursor protein (APP) transgenic mice or other mouse lines featuring alterations in lipoprotein metabolism, may provide new mouse models for elucidating the role of apoE2 in lipid homeostasis in the brain and in the pathogenesis of AD.
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PMID:Generation and characterization of two transgenic mouse lines expressing human ApoE2 in neurons and glial cells. 1213 50


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