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 cyclic AMP-mediated transcriptional regulation of the enzyme thyroperoxidase by thyrotropin (TSH) in thyroid follicular cells was examined at the molecular level. The 5' end of the human thyroperoxidase gene was isolated and sequenced and the transcription start site was mapped by S1 nuclease analysis. A 0.9 kilobase pair DNA fragment of the promoter was shown to confer responsiveness to thyrotropin, and cyclic AMP, in transient expression assays using two different reporter genes. Several potential sites for specific interaction with nuclear transcription factors which could be involved in the regulation of thyroperoxidase gene transcription were identified.
...
PMID:Thyroid peroxidase gene promoter confers TSH responsiveness to heterologous reporter genes in transfection experiments. 230 41

Glycogen accumulation in Escherichia coli is inversely related to the growth rate and occurs most actively when cells enter the stationary phase. The levels of the three biosynthetic enzymes undergo corresponding changes under these conditions, suggesting that genetic control of enzyme biosynthesis may account for at least part of the regulation (J. Preiss, Annu. Rev. Microbiol. 38:419-458, 1984). We have begun to explore the molecular basis of this control by identifying factors which affect the expression of the glycogen genes and by determining the 5'-flanking regions required to mediate the regulatory effects. The in vitro coupled transcription-translation of two of the biosynthetic genes, glgC (ADPglucose pyrophosphorylase) and glgA (glycogen synthase), was enhanced up to 26- and 10-fold, respectively, by cyclic AMP (cAMP) and cAMP receptor protein (CRP). Guanosine 5'-diphosphate 3'-diphosphate stimulated the expression of these genes 3.6- and 1.8-fold, respectively. The expression of glgB (glycogen branching enzyme) was affected weakly or negligibly by the above-mentioned compounds. Assays which measured the in vitro formation of the first dipeptide of glgC showed that a restriction fragment which contained 0.5 kilobases of DNA upstream from the initiation codon supported cAMP-CRP-activated expression. Sequence-specific binding of cAMP-CRP to a 243-base-pair restriction fragment from the region upstream from glgC was observed by virtue of the altered electrophoretic mobility of the bound DNA. S1 nuclease protection analysis identified 5' termini of four in vivo transcripts within 0.5 kilobases of the glgC coding region. The relative concentrations of transcripts were higher in the early stationary phase than in the exponential phase. Two mutants which overproduced the biosynthesis enzymes accumulated elevated levels of specific transcripts. The 5' termini of three of the transcripts were mapped to a high resolution. Their upstream sequences showed weak similarity to the E. coli consensus promoter. These results suggest complex transcriptional regulation of the glycogen biosynthesis genes involving multiple promoter sites and direct control of gene expression by at least two global regulatory systems.
...
PMID:Genetic regulation of glycogen biosynthesis in Escherichia coli: in vitro effects of cyclic AMP and guanosine 5'-diphosphate 3'-diphosphate and analysis of in vivo transcripts. 246 50

The Escherichia coli lacZ gene contains a series of latent transcriptional terminators that are responsible for the polar effects of certain mutations. We demonstrate, using gel electrophoretic size analyses and nuclease S1 mapping procedures, that RNA polymerase terminates RNA synthesis in the vicinity of five positions 180, 220, 379, 421 and 463 base-pairs downstream from the start point during transcription of lacZ DNA in vitro in the presence of rho factor. Termination at all but the 421 position depends on rho factor. In the in vitro assays with 0.05 M-KCl and excess rho (36 nM), the terminators are moderately effective, having efficiencies that range from about 8% at the 180 base-pair site to 56% at the 463 base-pair site. These termination stop points correspond to five of the 11 transcriptional pause sites between 180 and 463 base-pairs. Several stop points also correspond to 3' end points of lacZ mRNA isolated from cells containing the strongly polar lacZ-U118 mutation and from cells starved for serine, thus confirming that these latent terminators are responsible for the polar effect and demonstrating that they also function under a condition of physiological stress that prevents the transcription from being translated properly. Two other potential termination factors, NusA protein and cyclic AMP receptor protein have no effect in vitro on the efficiency of termination at the five lacZ sites.
...
PMID:Identification and characterization of transcription termination sites in the Escherichia coli lacZ gene. 247 37

A mutation in the gene IRA1 (formerly called PPD1) was originally characterized as a deficiency of a phosphoprotein phosphatase. The IRA1 gene has been cloned and sequenced. A large open reading frame (8,817 base pairs) which can encode a protein of 2,938 amino acids was found. Northern (RNA) blot analysis detected a message of about 10 kilobases, and nuclease S1 protection demonstrated mRNA start points at 97 and 98 base pairs upstream from the putative initiator ATG codon. Disruption of the IRA1 gene resulted in sensitivity to nitrogen starvation and heat shock. Diploids homozygous for the disrupted IRA1 gene were deficient in sporulation. Disruption of the IRA1 gene suppressed the lethality of the cdc25 mutation but did not suppress the lethality of either the ras1 ras2 or the cyr1 mutations. Deficiency of the phosphoprotein phosphatase was not reproducible in the disruption mutant of the IRA1 gene. Moreover, the ira1 mutant showed an increased level of cyclic AMP. Our results suggest that the IRA1 protein inhibits the function of the RAS proteins in a fashion antagonistic to the function of the CDC25 protein in the RAS-cyclic AMP pathway in Saccharomyces cerevisiae.
...
PMID:IRA1, an inhibitory regulator of the RAS-cyclic AMP pathway in Saccharomyces cerevisiae. 254 Apr 26

The maltose regulon of Escherichia coli comprises several operons that are under common regulatory control of the MalT activator protein. Five mal genes, organized in two divergent operons, code for a binding-protein-dependent transport system specific for maltose and maltodextrins. MalK, one of the subunits of this transport system, not only is essential for transport but also plays a role in regulation. Mutations abolishing MalK function not only result in inability to transport maltose but also cause constitutive expression of the maltose regulon. For this constitutivity to be exerted, the function of an additional gene product, MalI, is necessary. Using the constitutive expression of a malK-lacZ fusion as a signal, we cloned the malI gene, expressed it in minicells, and determined its DNA sequence. The sequence predicted a protein of 34,729 molecular weight, in agreement with the apparent molecular weight of the protein (35,000) when expressed in minicells and analyzed by polyacrylamide gel electrophoresis and autoradiography. MalI exhibited high homology to the repressor proteins GalR, CytR, and LacI. When the amino acid sequences were appropriately aligned, MalI showed 28% identity to GalR, 21% to CytR, and 24% to LacI. Including conservative amino acid exchanges, these numbers increased to 69, 56, and 58%, respectively. The regions of high homology were clustered in particular at the N-terminal portion of the protein that includes the helix-turn-helix motif thought to be involved in DNA binding. The protein contained a short stretch of 30 amino acids that was surprisingly homologous to a sequence in MalT. The amino-terminal half of the protein exhibited significant homology with MalK. The transcriptional start of malI was determined by reverse transcriptase and by S1 nuclease mapping. We found a possible binding site for cyclic AMP receptor protein in the promoter region of malI as well as two perfect direct repeats of 14 base pairs with twofold symmetry indicating their possible role as operator sites. Upstream to malI we observed a divergent open reading frame that extended to the end of the sequenced DNA.
...
PMID:MalI, a novel protein involved in regulation of the maltose system of Escherichia coli, is highly homologous to the repressor proteins GalR, CytR, and LacI. 267 Aug 98

Two kinds of cDNA (types A and B) encoding human dopamine beta-hydroxylase (DBH) were isolated from a pheochromocytoma cDNA library. Type A (2.7 kb) and B (2.4 kb) encoded the same amino acid sequence and were different only in 3'-untranslated region. Type A contained 3'-extension of 300 bp at the end of type B. Subsequently, we isolated human DBH gene and analyzed genomic DNA by Southern hybridization. Human DBH gene (approximately 23 kb) was composed of 12 exons and existed as a single gene on genome. Exon 12 encoded 3'-terminal region of 1,013 bp of type A, including the 300 bp sequence. These results indicate that alternative use of two polyadenylation sites from a single DBH gene generates different mRNA types. This conclusion was supported by Northern hybridization and S1 nuclease mapping experiments. The ratio of type A and B mRNAs in pheochromocytoma was roughly 1.0 to 0.2. We found possible transcription regulatory elements, TATA, CCAAT, CACCC, GC boxes, near the transcription initiation site of DBH gene. Sequences homologous to glucocorticoid and cyclic AMP response elements were also observed.
...
PMID:Human dopamine beta-hydroxylase gene: two mRNA types having different 3'-terminal regions are produced through alternative polyadenylation. 292 61

A nuclease S1 mapping procedure was used to identify sites accessible to nucleases in the 3'-noncoding region of the rabbit globin mRNAs. A complex structure was evident in the alpha-globin species, with one highly accessible single-stranded site, large portions in an accessible double-stranded configuration, and a portion not accessible to any of the nucleases. In the beta-globin mRNA, the region was more uniformly accessible to RNase T1 and to a cobra venom enzyme specific for double-stranded RNA, but it had only a single site highly accessible to a bulkier Neurospora endonuclease. The patterns of cleavage were nearly identical in the deproteinized mRNAs and in the mRNAs associated with polyribosomes in reticulocyte extracts. In both species, a zone of secondary structure occurred around the poly(A) junction. In each species, virtually all the molecules had a poly(A) sequence of at least 20-25 AMP residues. A periodicity in poly(A) size distribution was observed. These results indicate that the beginning of this sequence is well protected against degradation inside the cell and that zones of partial protection occur at measured intervals. In crude extracts, where the poly(A) is covered with proteins, this sequence was protected against nuclease digestion.
...
PMID:Structural features in the 3'-terminal region of polyribosome-bound rabbit globin messenger RNAs. 300 Oct 55

Gene 33, a rat gene transcriptionally enhanced by glucocorticoids, insulin, or cyclic AMP, was isolated from a library of rat genomic DNA and characterized by sequence comparison to a full-length cDNA. The structural gene spans 13,500 bp encoding 2970 bp of exon sequences interrupted by three introns of about 9600, 101 and 811 bp, respectively. Exons (5' to 3') are 198, 194, 77 and 2501 bp in length; the first of these initiates at the transcriptional start point determined by S1 nuclease mapping. The 5'-flanking DNA contains several putative transcriptional control elements including TATA and CAAT boxes and a binding site for the Sp1 transcription factor in the usual locations proximal to the start point. Sequences resembling known glucocorticoid and cyclic AMP regulatory elements are also found upstream. A chimeric plasmid was constructed containing putative gene 33 regulatory elements fused to the Escherichia coli gene cat, encoding the enzyme chloramphenicol acetyltransferase, and transfected into cultured fibroblasts. Transient expression assays established that this gene 33 DNA is effective in promoting transcription.
...
PMID:Structure of a multihormonally regulated rat gene. 322 31

A transcript analysis of the citrate synthase and succinate dehydrogenase genes (gltA-sdhCDAB) of Escherichia coli was done by nuclease S1 mapping. Evidence was obtained for two monocistronic gltA transcripts extending anti-clockwise, to a common terminus, from independent promoters with start points 196 bp (major) and 299 bp (minor) upstream of the gltA coding region. Evidence was also obtained for two polycistronic sdh transcripts, sdhCDAB (minor) and sdhDAB (major), extending clockwise, from sites 219 bp upstream of sdhC and 1455 bp upstream of sdhD (i.e. within sdhC), to a common terminus. The synthesis of all of the transcripts was repressed by growth in the presence of glucose, and this is consistent with the well-established fact that both enzymes are subject to catabolite repression. Sequences resembling known binding sites for the cAMP-CRP (cyclic AMP-cyclicAMP receptor protein) complex occur in the vicinity of each promoter suggesting that they are activated by the cAMP-CRP complex.
...
PMID:Transcript analysis of the citrate synthase and succinate dehydrogenase genes of Escherichia coli K12. 330 32

The total sequence of a 13,021 base-pair (bp) genomic fragment containing the rat L-type pyruvate kinase (L-PK) gene was determined by "shot gun" sequencing. This fragment includes 8360 bp of the L-PK gene, plus 3193 bp of the 5'-flanking and 1468 bp of the 3'-flanking regions. Like the chicken PK-M1 gene, the rat L-PK gene exhibits a fully conserved exon-intron structure, with 11 exons and 10 introns. In the chicken M1 gene, the coding sequences are well conserved (about 70%), in particular at the level of the exons implicated in the formation of PK active sites, exons that are also partially homologous to the corresponding sequences of the yeast gene. Various types of repetitive sequences exist in the L-PK gene, especially two ID (identifier) sequences located in the second intron and the 11th exon. Elements very similar to the "cyclic AMP-dependent regulatory element" recently described in the phosphoenolpyruvate carboxykinase and somatostatin genes are found in the sequenced fragment, but far upstream (-2338) and downstream (+5788) from the cap site. Various sequences homologous to described regulatory elements (glucocorticoid regulatory elements, enhancers, potential Z-DNA) are also observed 5' and 3' of the cap site. A comparison of the 5'-flanking region of the L-PK gene with the same regions of liver-specific or non-specific, cyclic-AMP-responsive or non-responsive genes was also made. It revealed various potentially interesting features that will be used to guide a further functional study. The cap site was determined by primer extension and nuclease S1 mapping using either mature mRNA or precursor RNA as templates. With both templates the start site of transcription appeared to be microheterogeneous, 19 to 14 bp before the ATG translation initiation codon.
...
PMID:Structure of the rat L-type pyruvate kinase gene. 330 48


<< Previous 1 2 3 4 Next >>

---