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

---

Query: EC:3.1.30.1 (S1 nuclease)
3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Wilms' tumor gene WT1 is a recessive oncogene that encodes a putative transcription factor implicated in nephrogenesis during kidney development. In this report we analyze expression of WT1 in the murine urogenital system. WT1 is expressed in non-germ-cell components of the testis and ovaries in both young and adult mice. In situ mRNA hybridization studies demonstrate that WT1 is expressed in the granulosa and epithelial cells of ovaries, the Sertoli cells of the testis, and in the uterine wall. In addition to the 3.1-kb WT1 transcript detected by Northern blotting of RNA from kidney, uterus, and gonads, there is an approximately 2.5-kb WT1-related mRNA species in testis. The levels of WT1 mRNA in the gonads are among the highest observed, surpassing amounts detected in the embryonic kidney. During development, these levels are differentially regulated, depending on the sexual differentiation of the gonad. Expression of WT1 mRNA in the female reproductive system does not fluctuate significantly from days 4 to 40 postpartum. In contrast, WT1 mRNA levels in the tesis increase steadily after birth, reaching their highest expression levels at day 8 postpartum and decreasing slightly as the animal matures. Expression of WT1 in the gonads is detectable as early as 12.5 days postcoitum (p.c.). As an initial step toward exploring the tissue-specific expression of WT1, DNA elements upstream of WT1 were cloned and sequenced. Three putative transcription initiation sites, utilized in testis, ovaries, and uterus, were mapped by S1 nuclease protection assays. The sequences surrounding these sites have a high G + C content, and typical upstream CCAAT and TATAA boxes are not present. These studies allowed us to identify the translation initiation site for WT1 protein synthesis. We have also used an epitope-tagging protocol to demonstrate that WT1 is a nuclear protein, consistent with its role as a transcription factor. Our results demonstrate regulation of WT1 expression during development of the gonads, implicate WT1 in genitourinary development, and provide a molecular framework toward understanding genitourinary defects observed among hereditary cases of Wilms' tumor.
...
PMID:Expression of the Wilms' tumor gene WT1 in the murine urogenital system. 165 Dec 75

To gain insight into the normal controls mediating expression of the c-Ki-ras protooncogene, we have identified DNA sequence elements within its promoter that are essential for transcriptional activity. Transient expression assays using the bacterial chloramphenicol acetyltransferase gene were used initially to localize regions directing primary promoter function. Stepwise deletion of 5' promoter sequences resulted in a gradual decrease in the ability to drive transcription of the reporter gene, suggesting that this promoter is composed of multiple cis-acting elements. Gel mobility-shift and DNase protection studies involving a 166-base-pair DNA fragment allowed the identification of protein-binding sites corresponding to these multiple regulatory elements. One element demonstrating particular transcriptional influence exists as a homopurine/homopyrimidine-rich region that in vitro exhibits S1 nuclease sensitivity and binds at least one nuclear protein. Data from competition binding experiments suggest that this nuclear factor may be influential in the regulation of other essential growth-control genes as well.
...
PMID:An S1 nuclease-sensitive homopurine/homopyrimidine domain in the c-Ki-ras promoter interacts with a nuclear factor. 218 46

The epidermal growth factor (EGF) receptor is the functional target of the mitogen EGF and the cellular homolog of the avian erythroblastosis virus erbB oncogene product. Regulation of expression of the proto-oncogene encoding the EGF receptor can be elucidated by studying the structure and function of the gene promoter outside the confines of the cell. Previously, we reported the isolation of the human EGF receptor gene promoter. The promoter is highly GC rich, contains no TATA or CAAT box, and has multiple transcription start sites. An S1 nuclease-sensitive site has now been found 80 to 110 base pairs (bp) upstream from the major in vivo transcription initiation site. Two sets of direct repeat sequences were found in this area; both conform to the motif TCCTCCTCC. When deletion mutations were made in this region of the promoter by using either Bal 31 exonuclease or S1 nuclease, we found that in vivo activity dropped three- to fivefold, on the basis of transient-transfection analysis. Examination of nuclear protein binding to normal and mutated promoter DNAs by gel retardation analysis and DNase I footprinting revealed that two specific factors bind to the direct repeat region but cannot bind to the S1 nuclease-mutated promoter. One of the specific factors is the transcription factor Sp1. The results suggest that these nuclear trans-acting factors interact with the S1 nuclease-sensitive region of the EGF receptor gene promoter and either directly or indirectly stimulate transcription.
...
PMID:Modulation of epidermal growth factor receptor proto-oncogene transcription by a promoter site sensitive to S1 nuclease. 284 30

5'-Flanking sequences from the human atrial natriuretic factor (hANF) gene were subcloned into a reporter plasmid (pSVOCAT) and transfected into primary cultures of neonatal rat atrial cardiocytes. Hybrid hANFCAT genes containing either 2500 or 409 base pairs of 5'-flanking sequence DNA were expressed at similar levels. When sequences between -409 and -332 were deleted, reporter gene (CAT) activity decreased significantly. Expression of the hANFCAT constructs was specific for atrial cells, as no expression was detected in primary cultures of ventricular cardiocytes or nonmyocardial cells derived from the neonatal hearts. Correct transcription start sites for the transfected hANF genes were confirmed by S1 nuclease mapping and RNase protection analysis. A "gel shift" assay was used to identify a specific cardiac nuclear protein which bound to the 5'-flanking sequence of the hANF gene. A 192-base pair PvuII fragment (-400 to -208) associated with a protein in these extracts in a tissue- and sequence-specific fashion. These findings indicate that the DNA sequence between -409 and -332 in the hANF gene harbors a tissue-specific element whose activity may involve association with a cardiac-specific nuclear protein.
...
PMID:Upstream sequences confer atrial-specific expression on the human atrial natriuretic factor gene. 296 19

DNA sequence-specific binding proteins eluted from chicken erythrocyte and thymus nuclei, and fractionated as described by Emerson and Felsenfeld (19), have been investigated by filter binding and footprint analyses. The erythrocyte nuclear protein fraction specifically binds to at least two sites within the 5' flanking chromatin hypersensitive site of the chicken beta A-globin gene, and to a site 5' to the human beta-globin gene. The major chicken beta A globin gene binding site [G)18CGGGTGG) and the human beta-globin gene binding site [TA)6(T)8C(T)4) occur at or near sequences which are hypersensitive to S1 nuclease cleavage in supercoiled plasmids. Downstream, the second chicken beta A-globin gene binding site includes the beta-globin gene CACCC consensus sequence. Filter binding studies also show other sequence specific binding activities to human N-ras and human (but not chicken) c-myc gene sequences.
...
PMID:Multiple sequence-specific DNA binding activities are eluted from chicken nuclei at low ionic strengths. 298 85

In the proviral DNA of mouse mammary tumor virus (MMTV), sequences up to approximately equal to 200 base-pairs from the RNA start site are required for stimulation of transcription by glucocorticoid hormones in cultured cells. A total of 26 mutant plasmids with clustered point mutations or small deletions in the hormone control region of the MMTV long terminal repeat were constructed, linked to the coding portion of the Herpes simplex virus thymidine kinase gene, and introduced by transfection into LTK- cells. Transcription from mutant DNA in the presence or absence of hormone was quantified by S1 nuclease protection assays. Our analysis revealed the presence of at least three control elements that affect the extent of transcription stimulation by glucocorticoid hormones: (1) a distal element, between -181 and -172 base-pairs from the RNA initiation site. Linker scanning mutants in this segment have a reduction of up to 20-fold in the hormone response with respect to wild type. (2) An element around position -120, defined by a mutation of 4 base-pairs between -121 and -117, which causes a fivefold reduction. (3) An element from approximately equal to -78 to -70, defined by a mutant with also a roughly fivefold lower stimulation. The first two are included in areas that have been shown by others to interact in vitro with hormone-receptor complexes; the last one overlaps the in vitro binding site of a nuclear protein factor. A mutant lacking all three elements (-193 to -70) is completely non-inducible by glucocorticoids. Together with earlier results obtained with 5' deletion mutants, the data show that the largest contribution to the stimulatory response is made by the distal element, which however does require the presence of both more-proximal ones for the response to be maximal. In the absence of the distal one, the two proximal elements together produce a residual stimulation in the order of 5 to 10% of wild type, while the -70 element alone is ineffective. In addition, we show that a functional TATA homology is required for maximum stimulation. It appears that transcriptional regulation of MMTV by glucocorticoid hormones is achieved by the concerted action of multiple sequence modules, not all of which correspond to receptor binding sites in vitro.
...
PMID:Distinct sequence elements involved in the glucocorticoid regulation of the mouse mammary tumor virus promoter identified by linker scanning mutagenesis. 302 41

Diminished cellular responsiveness to transforming growth factor-beta (TGF-beta) is frequently correlated with decreased transcription of the type II receptor for TGF-beta (TGF-beta RII). We have cloned and characterized the human TGF-beta RII promoter and, using S1 nuclease mapping and 5' rapid amplification of cDNA ends polymerase chain reaction, have identified five alternative transcription start sites within the region -33 to +57. DNA transfection experiments and electrophoretic mobility shift assays have revealed the existence of five distinct regulatory regions including two positive regulatory elements and two negative regulatory elements in addition to the core promoter region. The first positive regulatory element (-219 to -172) interacts with two distinct nuclear protein complexes, at least one of which appears to be a previously unidentified transcription factor. The second positive regulatory element (+1 to +35) also interacts with two separate protein complexes, both of which appear to be novel transcription factors. Deletion of either positive regulatory element markedly decreased expression of the target gene, suggesting that both positive regulatory elements are necessary for basal expression levels of TGF-beta RII.
...
PMID:Characterization of the promoter region of the human transforming growth factor-beta type II receptor gene. 749 85

We have identified two regions of non-random purine/pyrimidine strand asymmetry that were nearly identical in sequence in the 5' flanking (promoter) regions of the human cystic fibrosis transmembrane conductance regulator (CFTR) gene and the human MUC1 gene. These regions contain perfect mirror repeat elements, a sequence motif previously found to be associated with the formation of H-DNA conformations. In this report we demonstrate that a single-stranded non-B DNA conformation exists at low pH in supercoiled plasmids containing the similar mirror repeat elements, and that S1 nuclease digestion maps the single-stranded region to the position of the mirror repeats. In addition, we identify a nuclear protein of approximately 27 kD that binds to single-stranded oligonucleotides corresponding to the purine-rich strand of this region, but not to the pyrimidine-rich strands or to double-stranded oligonucleotides with corresponding purine/pyrimidine strand asymmetry.
...
PMID:A nuclear factor that binds purine-rich, single-stranded oligonucleotides derived from S1-sensitive elements upstream of the CFTR gene and the MUC1 gene. 751 81

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.
...
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

In the mouse mammary tumor virus promoter, a tandem of octamer motifs, recognized by ubiquitous and tissue-restricted Oct transcription factors, is located upstream of the TATA box and next to a binding site for the transcription factor nuclear factor I (NF-I). Their function was investigated with mutant long terminal repeats under different transfection conditions in mouse Ltk- cells and quantitative S1 nuclease mapping of the transcripts. In stable transfectants, which are most representative of the state of proviral DNA with respect to both number of integrated DNA templates and chromatin organization, a long terminal repeat mutant of both octamer sites showed an average 50-fold reduction of the basal transcription level, while the dexamethasone-stimulated level was unaffected. DNase I in vitro footprinting assays with L-cell nuclear protein extracts showed that the mutant DNA was unable to bind octamer factors but had a normal footprint in the NF-I site. I conclude that mouse mammary tumor virus employs the tandem octamer motifs of the viral promoter, recognized by the ubiquitous transcription factor Oct-1, for its basal transcriptional activity and the NF-I binding site, as previously shown, for glucocorticoid-stimulated transcription. A deletion mutant with only one octamer site showed a marked base-level reduction at high copy number but little reduction at low copies of integrated plasmids. The observed transcription levels may depend both on the relative ratio of transcription factors to DNA templates and on the relative affinity of binding sites, as determined by oligonucleotide competition footprinting.
...
PMID:Stably integrated mouse mammary tumor virus long terminal repeat DNA requires the octamer motifs for basal promoter activity. 828


1 2 Next >>

---