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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A bovine genomic library was constructed using a cosmid vector, pHC79, and bovine DNA partially digested by EcoRI. Bovine P-450(11 beta) cDNA, pcP-450(11 beta)-2 [Morohashi et al. (1987) J. Biochem. 102,559-568], was used as a probe for screening the genomic library. Ten clones carrying P-450(11 beta) genomic DNA were isolated from 8 x 10(4) colonies and classified into five groups (CB11 beta-1, CB11 beta-3, CB11 beta-7, CB11 beta-20, and CB11 beta-21) according to differences in the restriction endonuclease sites. Nucleotide sequences of amino acid coding regions of the five clones were determined by the dideoxy sequencing method using synthetic nucleotides corresponding to various parts of the cDNA as primers. The nucleotide sequences revealed that three clones, CB11 beta-1, CB11 beta-3, and CB11 beta-21, were pseudogenes. Amino acid sequences coded by the other two clones, CB11 beta-7 and CB11 beta-20, were identical with that coded by a previously described cDNA, pcP-450(11 beta)-3 [Kirita et al. (1988) J. Biochem. 104, 683-686]. The promoter regions of the five clones were introduced in front of chloramphenicol acetyltransferase (CAT) gene of pSV00CAT and used to examine P-450(11 beta) gene regulation in cultured cells. The five recombinant plasmids showed cAMP-responsive CAT activities in Y-1 cells, a cell strain derived from adrenal tumor. The induction rates of the recombinant plasmids carrying the promoters of normal genes, CB11 beta-7 and -20, were larger than those of pseudogenes, CB11 beta-1, -3, and -21. CAT activities expressed by the promoter regions of the normal genes in the presence or absence of cAMP in Y-1 cells were almost equal to that by the promoter region of human P-450(SCC) gene. Though the promoter of the P-450(SCC) gene also showed cAMP-responsive CAT activity in I-10 cells, a cell strain derived from Leyding cell tumor, P-450(11 beta) gene promoter did not express the activity in I-10 cells.
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PMID:Structural analysis of multiple bovine P-450(11 beta) genes and their promoter activities. 196 87

Increases in the cAMP level are often inhibitory in mature T lymphocytes and may be involved in the development of tolerance to self Ag. In this report, agents inducing an increase in the cAMP level by independent mechanisms were found to stimulate DNA fragmentation, characteristic of a suicide program known as apoptosis, in isolated thymocytes. Data obtained with cAMP analogs known to act synergistically to stimulate protein kinase A suggested that the latter directly mediated endonuclease activation. Agents previously shown to stimulate protein kinase C and to inhibit Ca2(+)-dependent, TCR-mediated thymocyte apoptosis, including IL-1, also blocked both DNA fragmentation and cell death in response to cAMP, suggesting interactions ("cross-talk") between the two protein kinase systems. As it has been proposed that apoptosis mediates negative cell selection in the thymus, our results indicate that cAMP may play a role in the development of functional mature T lymphocytes.
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PMID:Agents that elevate cAMP stimulate DNA fragmentation in thymocytes. 216 10

We describe the construction of a new generation of vectors (pRE) for the hyperexpression of lethal gene products such as adenylate cyclase in Escherichia coli. The pRE vectors are based on the lambda PL promoter and lambda cII ribosome binding site described by Shimatake and Rosenberg (Nature, 292, 128-132, 1981). They have a unique NdeI restriction endonuclease site 3' of the lambda cII ribosome binding site that includes the ATG initiation codon, multilinker cloning sites 3' to the NdeI site, and two lambda transcription terminators 5' and 3' of the lambda PL promoter to eliminate nonspecific transcription and reduce leaky PL transcription, respectively. For hyperexpression of adenylate cyclase, tight control of transcription was necessary since elevation of cAMP levels above the physiological range is lethal to E. coli. Lethality associated with the overproduction of adenylate cyclase was shown to be mediated through the cAMP receptor protein. We used this expression system to overproduce adenylate cyclase 7500 fold, corresponding to 30% of the total cellular protein. Under these conditions the enzyme precipitated with significant loss of activity. Reducing the rate and amount of adenylate cyclase expression to 16% of the total cell protein produced one fourth of the enzyme in a soluble form with high specific activity. The soluble adenylate cyclase was purified to near homogeneity.
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PMID:Hyperexpression and purification of Escherichia coli adenylate cyclase using a vector designed for expression of lethal gene products. 255 91

The structural organization of the X-linked gene for the E1 alpha subunit of the human pyruvate dehydrogenase complex has been determined by restriction endonuclease mapping and DNA sequence analysis of overlapping genomic clones. The gene is approximately 17 kilobase pairs long. It contains 11 exons ranging from 61 to 174 base pairs and introns ranging from 600 base pairs to 5.7 kilobase pairs. All the splice donor and acceptor sites conform to the GT/AG rule. The transcription initiation site was determined by S1 nuclease mapping. The DNA sequence around this site is very GC-rich. A "TATA box"-like sequence and a "CAAT box"-like sequence are present 24 and 113 bases upstream from the cap site, respectively. Also upstream from the cap site are several sets of inverted repeats, direct repeats, several sequences resembling the transcription factor Sp1 binding site, a glucocorticoid-responsive element, and two cAMP receptor binding sites.
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PMID:Structural organization of the gene for the E1 alpha subunit of the human pyruvate dehydrogenase complex. 274 44

The gene for cytosolic phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) from the chicken was isolated from a recombinant library containing the chicken genome in phage lambda Charon 4A. The isolated clone, lambda PCK1cc, contains the complete gene for the enzyme as well as both 5' and 3' flanking sequences. The gene is approximately 8 kilobases in length divided into 8 exons, as demonstrated by restriction endonuclease mapping and DNA-RNA heteroduplex analysis. Southern blotting of chicken chromosomal DNA digested with various restriction enzymes shows a pattern predicted from the restriction map of lambda PCK1cc. The phosphoenolpyruvate carboxykinase gene is present as a single copy in the haploid chicken genome. The 5' region of the gene was defined by S1 nuclease mapping and by sequencing. Two mRNA species with discrete 5' ends were observed using S1 nuclease mapping. The ratio between the amounts of these multiple forms of mRNA is the same in chicken kidney and liver and is not affected by induction of the enzyme mRNA by cAMP. Examination of sequence homologies with the gene for rat cytosolic phosphoenolpyruvate carboxykinase indicates a putative control region contained in flanking sequences at the 5' end of the gene.
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PMID:The gene encoding the cytosolic form of phosphoenolpyruvate carboxykinase (GTP) from the chicken. 609 81

Familial male-limited precocious puberty (FMPP) is an autosomal dominant disorder characterized by marked elevation of serum testosterone despite low levels of gonadotropin. Recently, a single point mutation in the LH/hCG receptor (LH/CGR) gene was found in FMPP families that constitutively activates the LH/CGR, causing Leydig cell activation and precocious puberty. Among the Japanese population, only four sporadic cases of male-limited precocious puberty have been reported. In the current study, we examined one of the four reported Japanese patients with sporadic male-limited precocious puberty and found the same mutation as that in the FMPP families. Genomic DNA was isolated, and the polymerase chain reaction (PCR) was performed to amplify a fragment of LH/CGR DNA encoding amino acid residues that include transmembrane helixes 5 and 6. Sequencing of the PCR products revealed a heterozygous adenosine-guanine transition at nucleotide 1733 in codon 578. The mutation encodes an aspartic acid578-glycine substitution in transmembrane helix 6. The mutant LH/CGR, created by site-directed mutagenesis in vitro, exhibited constitutively higher cAMP levels in transfected COS-7 cells than the wild-type LH/CGR, as described previously; however, basal inositol phosphate levels were not increased by transfection with complementary DNA for the mutant receptor. The concentration and affinity of [125I]hCG-binding sites were similar in cells transfected with the mutant and wild-type LH/CGR complementary DNAs, indicating that the mutant did not alter the production of receptor or its ability to bind human LH/CG. The sporadic occurrence of this case was confirmed by further studies. The mutation creates a recognition site for the restriction endonuclease MspI. Restriction digestion was positive for the mutant not digested by MspI, indicating that the patient's mutant allele was not inherited from his parents. DNA analysis of the patient and the parents, using microsatellite repeat markers, was compatible with biological paternity and maternity. We conclude that the aspartic acid578-->glycine mutation in the LH/CGR has arisen in the Japanese population and is the cause of a sporadic case of male-limited precocious puberty.
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PMID:A sporadic case of male-limited precocious puberty has the same constitutively activating point mutation in luteinizing hormone/choriogonadotropin receptor gene as familial cases. 752 13

The complete organization of the human luteinizing hormone-choriogonadotropin (LH/CG) receptor (LH/CGR) gene and the structure of 1591 bp of its 5' flanking region have been determined. This gene spans over 70 kbp and contains 11 exons. The first ten exons and part of the last exon encode the extracellular domain of the receptor while the transmembrane and intracellular domains are encoded by the remaining part of the last exon. The gene encodes a 701 amino acids long preprotein, contrary to a previous report of 699 amino acids. Primer extension experiments and polymerase chain reaction (PCR) mapping allowed definition of the transcription initiation site, which is located 1085 bp upstream from the initiation codon. The 5' non-coding region is thus unusually long. The promoter region which is different from the murine LH/CG receptor promoter, contains two putative TATA boxes at positions -34 and -47 and a CAAT box consensus sequence at position -89. A consensus sequence corresponding to a cAMP responsive element is found at position -697. Seven API consensus sequences are also found in the 5' flanking region of the gene. Southern blot experiments demonstrated an informative biallelic polymorphism within the human LH/CG receptor gene locus using BglII endonuclease. The cloning of the human LH/CGR gene and the determination of the organization and structure of its 5' flanking region allow the study of its hormonal, developmental and tissue-specific regulation. Primers and PCR conditions are described for the direct genomic sequencing of all the exons of the gene. This information should facilitate the study of pathological mutations of the receptor.
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PMID:Structure of the human luteinizing hormone-choriogonadotropin receptor gene: unusual promoter and 5' non-coding regions. 755 72

To define the mechanisms of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced transcription of the ornithine decarboxylase (ODC) gene, we isolated a genomic clone (hODC41B) of ODC from a human leukocyte genomic DNA library. The restriction endonuclease map, in comparison with the previously published sequences of the human ODC gene, indicated that hODC41B contained a 15.7-kb sequence that extended from the sixth exon to about 10 kb upstream of the ODC gene. A 2.5-kb genomic fragment containing the 5' flanking region and the first exon was subcloned and sequenced. Sequence analysis revealed multiple putative promoter/enhancer elements (a TATA box, a CAAT box, 17 GC boxes, and a cAMP-responsive element) but no consensus AP-1 sequences (TGAGTCA) in the 2.5-kb 5' flanking region. However, three AP-1 sequences were located in introns 3, 5, and 11. We constructed a series of chimeric genes containing part of the first exon and increasingly longer 5' flanking sequences of the ODC gene fused to either bacterial chloramphenicol acetyltransferase (CAT) or luciferase reporter genes. TPA inducibility was determined by transient transfection and measurement of CAT or luciferase expression in HeLa cells. The induction of CAT activity by TPA decreased with decreasing lengths of the 5' flanking sequences up to nt -82. The TPA induction from the construct -72 ODC CAT was threefold to sevenfold, and the TPA inducibility of the same fragment was about ninefold to 30-fold with the luciferase reporter gene. Further deletion analysis revealed TPA-responsive sequences in ODC nt -42 to +54. Gel mobility shift assays using alpha-32P-end labeled ODC nt -42 to +60 revealed that nt -42 to +60 specifically bound HeLa cell nuclear proteins. HeLa cell nuclear protein binding to ODC nt -42 to +60 could not be completely competed by AP-1-, AP-2-, AP-3-, or SP1-responsive sequences.
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PMID:Non-AP-1 tumor promoter 12-O-tetradecanoylphorbol-13-acetate-responsive sequences in the human ornithine decarboxylase gene. 804 98

The present study was undertaken to determine whether specific interactions between cAMP and glucocorticoids regulate apoptosis in thymocytes. Incubation of murine thymocytes with agents that elevate the cAMP level resulted in enhancement of glucocorticoid-induced Ca2+ increases, DNA fragmentation, and cell death compared to levels observed in thymocytes treated with steroid alone. cAMP did not affect DNA fragmentation in thymocytes treated with Ca2+ ionophore, a compound that induces endonuclease activation via an independent mechanism. Treatment with cAMP also increased glucocorticoid potency by lowering the concentration of steroid required for induction of apoptosis. The mechanism of cAMP action appeared to involve the glucocorticoid receptor, since the glucocorticoid antagonist RU-486 abrogated the cAMP response in animals treated with the adenosine analog NECA in vivo. Analysis of cellular glucocorticoid binding and receptor protein levels revealed modest cAMP-stimulated increases that appeared insufficient to account for the effects of cAMP on endogenous endonuclease activation, suggesting the possible involvement of a posttranslational mechanism in the response. These results demonstrate that cAMP and glucocorticoids synergize to promote apoptosis in thymocytes via a mechanism that appears to involve modification of glucocorticoid receptor activity.
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PMID:Cyclic AMP potentiates glucocorticoid-induced endogenous endonuclease activation in thymocytes. 838 20

A model system has been established in which PC12 cells are converted to neuronal-like cells that undergo transcription-dependent cell death following removal of NGF. Nineteen sublines of PC12 cells were tested to establish parameters for making cells dependent on NGF for survival. In most sublines, a relatively small percentage of cells become dependent on NGF for survival, and following removal of NGF, most of the cells begin proliferating in serum-containing medium. In several sublines, however, a significant percentage of cells die following removal of NGF. One of these sublines, PC6-3, can be grown under conditions in which 90% of the cells undergo transcription-dependent cell death following removal of NGF in either serum-free or serum-containing medium. Fourteen hours after removing NGF, 50% of the cells are committed to die, while initial morphological signs of cell death as determined by time-lapse videomicroscopy occur 2-6 hr later and include loss of neurites followed by a 1-3 hr period of active membrane "blebbing" and protrusions. Cell death can be blocked by the RNA synthesis inhibitor actinomycin D, the protein synthesis inhibitor cycloheximide, KCl, basic fibroblast growth factor, or dibutryl-cAMP, but not by epidermal growth factor, leupeptin, or the endonuclease inhibitor aurintricarboxylic acid (ATA). Removal of NGF activates an endonuclease that causes nucleosomal laddering of the DNA; however, endonuclease activity does not appear to be required for cell death. In agreement with previous studies (Batistatou and Greene, 1991; Rukenstein et al., 1991) demonstrating that naive PC12 cells undergo transcription-independent cell death when shifted into serum-free medium in the absence of growth factors, all cell lines tested except for one die when cultured in RPMI medium lacking growth factors. DNA fragmentation is a prominent feature of transcription-independent cell death, and death can be blocked with NGF, ATA, and dibutryl-cAMP but not with actinomycin D or KCl. The PC12 model system described here should be useful for identifying cell death genes and for characterizing cellular and molecular events in programmed neuronal cell death.
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PMID:A system for characterizing cellular and molecular events in programmed neuronal cell death. 839 68


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