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)

Bovine pancreatic deoxyribonuclease I (DNase I), an endonuclease that degrades double-stranded DNA in a nonspecific but sequence-dependent manner, has been used as a biochemical tool in various reactions, in particular as a probe for the structure of chromatin and for the helical periodicity of DNA on the nucleosome and in solution. Limited digestion by DNase I, termed DNase I 'footprinting', is routinely used to detect protected regions in DNA-protein complexes. Recently, we have solved the three-dimensional structure of this glycoprotein (relative molecular mass 30,400) by X-ray structure analysis at 2.5 A resolution and have subsequently refined it crystallographically at 2.0 A. Based on the refined structure and the binding of Ca2+-thymidine 3',5'-diphosphate (Ca-pTp) at the active site, we propose a mechanism of action and present a model for the interaction of DNase I with double-stranded DNA that involves the binding of an exposed loop region in the minor groove of B-DNA and electrostatic interactions of phosphates from both strands with arginine and lysine residues on either side of this loop. We explain DNase I cleavage patterns in terms of this model and discuss the consequences of the extended DNase I-DNA contact region for the interpretation of DNase I footprinting results.
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PMID:Structure of DNase I at 2.0 A resolution suggests a mechanism for binding to and cutting DNA. 371 45

Human lung cells (ChaGo) derived from a bronchogenic carcinoma produce human chorionic gonadotropin (hCG), predominantly the alpha subunit of the glycoprotein hormone, under culture conditions. Treatment of the cells with the polycyclic aromatic hydrocarbons, benzo(a)pyrene (BaP) or dimethylbenzanthracene, at concentrations which do not affect cell growth or macromolecular synthesis, stimulates the production of hCG in these cells. The levels of alpha hCG-specific mRNA (mRNA alpha hCG) sequences in total poly(A)+ RNA isolated from control and drug-treated ChaGo cells are determined by the dot hybridization technique using 32P-labeled, cloned cDNA alpha hCG probe. A concentration-dependent increase in the levels of mRNA alpha hCG sequences in BaP or dimethylbenzanthracene-treated ChaGo cells has been observed. The increase in the level of mRNA alpha hCG sequences can be detected after treatment of the cells with either of the drugs for 24 h, and this level attains its maximum within 48-72 h following drug treatment. A comparative study of the restriction endonuclease (MspI/HpaII) digestion patterns of the control and BaP-treated cell DNA suggests that the internal "C" residues of the -CCGG- sequences in the alpha hCG gene of untreated cells are highly methylated; whereas the internal C residues of the same MspI/HpaII recognition sequences in the alpha hCG gene are comparatively less methylated in BaP-treated cell DNA.
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PMID:Mechanism of induction of human chorionic gonadotropin in lung tumor cells in culture. Increased levels of alpha-human chorionic gonadotropin-specific mRNA sequences and benzo(a)pyrene-induced hypomethylation. 608 14

The primary structure analysis of the gag gene products of human T-cell leukemia virus (HTLV)-ICR has been nearly completed. A comparison of the amino acid sequences with the published nucleotide sequence of HTLV-IATK established that i) p19 which is known to share antigenic determinants with a protein present in normal thymic epithelium, is nevertheless virally coded. ii) The gene order and complete primary structure of the gag precursor (Pr55) which has been shown to be myristylated (My) at its N-terminus is My-p19-p24-p15-OH; and iii) the Pr55gag amino acid sequences of HTLV-ICR and HTLV-IATK are nearly identical showing only a single residue difference in the C-terminal region of p15. Antibodies to synthetic peptides inferred from the nucleotide sequence of the env gene of HTLV-IATK were also raised and used to identify and purify env precursor gPr62-68, surface glycoprotein gp46-51 and transmembrane protein p21. While most of the peptide sera were shown to be subgroup specific some of them detected antigenic determinants shared between protein homologs of viruses of subgroups I and II. Partial or complete amino acid sequences of both the gag and env gene coded proteins of bovine leukemia virus (BLV) structural proteins have also been determined. These extensive protein data together with nucleotide sequences confirm and extend our initial finding that HTLV and BLV are structurally and antigenically related and may have originated from common ancestor. The structural and immunological studies revealed also relationships between HTLV and a number of type C and type D retroviruses studied. One of the highly conserved sequences is shared by the transmembrane proteins of these retroviruses which have been implicated in immunosuppression. It is conceivable that these common regions have common biological function. Two previously unidentified proteins of BLV have also been purified and structurally characterized. Nucleotide sequences capable of coding for related products are present in HTLV. The nature and possible biological functions of these new BLV proteins and the putative HTLV gene products will be discussed. The size and complexity of the genome of the replication competent retroviruses are similar but not identical. The 35S RNA of all replication competent helper viruses is divided into three genes encoding the viral structural proteins: the gag (group-specific antigen) gene codes for the internal structural proteins, the pol (polymerase) gene codes for the enzymes protease, reverse transcriptase and endonuclease and the env (envelope) gene codes for the proteins of the viral envelope.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Structural and antigenic characterization of the proteins of human T-cell leukemia viruses and their relationships to the gene products of other retroviruses. 610 Jun 35

The ganglia of rabbits infected with a relatively benign strain of herpesvirus (E-43) and challenged with either of two virulent neurotrophic strains (MP or McKrae) were found to be colonized only by the initial benign infecting strain. Primary infection with the E-43 strain resulted in milder disease when the animals were infected with MP or McKrae strains and also prevented colonization of the ganglion by these strains. Neutralization with anti-glycoprotein C, plaque morphology, cytopathic effects, reconstruction experiments, and restriction endonuclease analysis indicated that the virus recovered from the ganglion was the initial infecting E-43 strain; no traces of the challenging MP and McKrae strains were found. The challenging McKrae strain was shed for several weeks in a few animals, but the virus isolated from the trigeminal ganglia of these animals was the primary infecting E-43 strain. These results suggest that initial infection with a relatively benign strain of herpesvirus may prevent superinfection of the ganglion (but not necessarily the end organ) by highly virulent herpes simplex virus strains and could have significant implications in the consideration of immunization against this disease in humans.
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PMID:Initial herpes simplex virus type 1 infection prevents ganglionic superinfection by other strains. 627 13

The gene encoding the common alpha subunit of the four human glycoprotein hormones, chorionic gonadotropin (CG), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH), has been cloned in a bacteriophage lambda vector. Restriction endonuclease digestion of total human DNA suggests that the common alpha subunit is coded for by a single gene. Three distinct polymorphic hybridization patterns have been observed for this gene in the human population. The cloned gene encompasses a total of 9.4 kilobases (kb) and contains three intervening sequences whose locations have been established by restriction enzyme mapping and by DNA sequencing. One of the intervening sequences is located in the 5' untranslated region, generating a leader sequence that is separated from the rest of the gene by 6.4 kb. The other two intervening sequences are 1.7 and 0.4 kb long and are located within codon number 6, and between codons 67 and 68, respectively. The location of the 5' end of the mature transcript has been established by priming placental mRNA with a restriction fragment obtained from the cloned cDNA. A transcript of similar size for the alpha subunit gene has been detected in both the pituitary, where the gene is expressed for the synthesis of LH, FSH, and TSH, and the placenta, where the gene is expressed for the synthesis of CG. When parts of the 5' untranslated nucleotide sequences of the alpha subunit and the human growth hormone genes are compared a highly homologous region is observed. These otherwise unrelated genes share the common feature that they encode a secreted pituitary polypeptide hormone.
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PMID:The gene encoding the common alpha subunit of the four human glycoprotein hormones. 628 17

The gene for the H-2K class I antigen of the bm1 variant was cloned and analyzed at the DNA level and compared with the previously cloned parent B6/Kh gene. Sequence determination and comparative restriction endonuclease studies indicate that Kbm1 is derived from the Kb gene. Seven nucleotide changes within a 13-nucleotide stretch distinguish the mutant from the parent gene and result in amino acid differences at positions 152, 155, and 156 in the antigen. The data confirm previously reported changes at amino acid positions 155 and 156 (arginine to tyrosine and leucine to tyrosine, respectively) and extend the altered region to include two nucleotides encoding a glutamate to alanine substitution at amino acid 152, a change not detected by the protein studies because of limitations of the methods used. The DNA sequence encoding this region of the Kbm1 glycoprotein is identical to the DNA sequence of at least one other known class I gene in the mouse, a finding consistent with the hypothesis that the mutation was not a random event but may be the result of a block transfer of information by a copy mechanism analogous to gene conversion. As the sequence analysis of the coding region for the first 273 amino acid residues shows identity between parent and mutant except for the seven nucleotide changes, all variant-parent functional differences must depend only on the cluster of three amino acid differences in the second domain of the Kb glycoprotein.
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PMID:Comparison of the cloned H-2Kbm1 variant gene with the H-2Kb gene shows a cluster of seven nucleotide differences. 630 Aug 87

We isolated and characterized two spontaneous, weakly leukemogenic mutants of Rauscher spleen focus-forming virus (R-SFFV) that contain mutations in nonoverlapping regions of the membrane envelope (env) glycoprotein gene. As reported previously (M. Ruta and D. Kabat, J. Virol. 35:844-853, 1980), the replication-defective R-SFFV encodes a membrane glycoprotein with an apparent Mr of 54,000 (gp54) which is structurally and immunologically related to the membrane envelope glycoproteins of dual-tropic murine leukemia viruses. Mutant R-SFFV clones 3-25 and 4-3 encode abnormally sized gp54-related glycoproteins with apparent Mrs of 52,000 (gp52) and 45,000 (gp45), respectively. Northern and Southern blot analyses of the mutant R-SFFV nucleic acids indicated that an insertion has occurred in the 3-25 env gene and that a deletion has occurred in the 4-3 env gene. Furthermore, restriction endonuclease analyses and comparisons of the fragmentation patterns of the wild-type and mutant glycoproteins generated by partial proteolysis with Staphylococcus aureus V8 protease indicated that the mutations affect nonoverlapping domains of the envelope glycoprotein (amino-terminal fragment affected in 3-25 glycoprotein and carboxyl-terminal fragment affected in 4-3 glycoprotein). Glycosylation inhibition studies indicated that the reduced size of gp52 is caused at least partly by loss of an asparagine-linked oligosaccharide. In addition, these mutant viruses have dramatically reduced leukemogenicities compared with wild-type R-SFFV. We conclude that the gp54 structural gene is required for initiation or amplification of the splenic erythroblast hyperplasia which characterizes the preleukemic phase of Rauscher disease.
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PMID:Reduced leukemogenicity caused by mutations in the membrane glycoprotein gene of Rauscher spleen focus-forming virus. 631 40

Two cDNA clones, pDRH1 and pDRH2, containing sequences specific for human HLA-DR antigens were isolated from a bank of cDNA clones made from partially purified HLA-DR mRNA from the human lymphoblastoid cell line Maja. The clones were specific for the Mr 34,000 HLA-DR antigen glycoprotein chain. The identity of these clones was established by (i) their ability to hybridize specifically to HLA-DR mRNA in a positive selection assay; (ii) mRNA species hybridizing to the cDNA clones were expressed in B-cell but not in T-cell or fibroblast cell cultures; and (iii) a nucleotide sequence in the longer clone, pDRH2, could be translated into an amino acid sequence that is identical to the limited NH2-terminal amino acid sequence available for the purified HLA-DR antigen Mr 34,000 chain. Analysis of DNA from human, mouse, and human--mouse somatic cell hybrid lines by Southern transfer of restriction endonuclease digests indicated that the HLA-DR heavy chain is encoded in chromosome 6. This finding is compatible with the location of at least one of the HLA-D/DR heavy chain genes within the HLA region. In addition, the sequences coding for HLA-DR heavy chain appear to be present in only one or a few copies in the genome and to be relatively simple in structure.
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PMID:cDNA clones coding for the heavy chain of human HLA-DR antigen. 695 7

A study of the genetic variability of herpes simplex virus (HSV) type 1 from recurrent lesions and clinical reinfections was done using restriction endonuclease analysis and the RNase A mismatch cleavage method. Comparative genetic analyses of HSV-1 recurrent isolates from 1 patient and of HSV-1 isolates from different anatomic areas (vagina and lip) from another patient showed differences only in the glycoprotein B gene but not in the thymidine kinase gene even though the viruses had the same restriction endonuclease pattern. These results suggest the RNase A mismatch cleavage method is useful for epidemiologic studies of DNA viruses.
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PMID:Genetic analysis of herpes simplex virus type 1 isolates from recurrent lesions and clinical reinfections. 759 26

The genetic stability of a live human adenovirus 5: rabies glycoprotein recombinant vaccine has been assessed upon 20 serial passages in a permissive cell line of human origin. Restriction endonuclease analysis and the polymerase chain reaction were used to examine the integrity of the expression cassette for the rabies glycoprotein and the viral vector at the site of insertion of the cassette. It was found that the restriction endonuclease profile was identical for each sample assayed. A more detailed analysis of the expression cassette following amplification by the polymerase chain reaction revealed no changes in the size and number of fragments originating from the coding sequence for the glycoprotein nor the signals controlling the expression of the protein product. The amplified product obtained from the 10th and 20th passages was subjected to nucleotide sequencing. Additionally, 20 plaques isolated from the 20th passage of the virus expressed the rabies glycoprotein as demonstrated by fluorescent antibody staining with glycoprotein specific monoclonal antibodies. These results suggest that the recombinant vaccine maintains the integrity of the heterologous sequences upon passage in tissue culture.
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PMID:In vitro assessments of the genetic stability of a live recombinant human adenovirus vaccine against rabies. 764 30


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