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W Bodemer

Publications and source records attributed to W Bodemer.

67 records · Page 4Linked to original sources
PubMed1986

The A+T-rich genome of Herpesvirus saimiri contains a highly conserved gene for thymidylate synthase.

Herpesvirus saimiri (HVS) is the prototype member of a distinctive subset of lymphotropic herpesviruses (the gamma 2 subgroup) with A+T-rich coding sequences. In this paper, we show that cells productively infected with HVS contain high concentrations of a virus-specified thymidylate synthase (5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45); we identify the active polypeptide and present the sequence of the virus gene. The predicted amino acid sequence of the 294-residue subunit of the virus enzyme is 70% homologous with the sequence of the human enzyme and about 50% homologous with prokaryotic thymidylate synthases, illustrating the remarkable structural constraints imposed by the thymidylate synthase function. However, the presence of the enzyme is not a conserved property of herpesviruses. We find no evidence for a virus-encoded thymidylate synthase activity (or a homology to a thymidylate synthase sequence) in G+C-rich representatives of alpha 1 (e.g., herpes simplex viruses, 66-68% G+C), beta (i.e., human cytomegalovirus, 58-59% G+C), and gamma 1 (i.e., Epstein-Barr virus, 60% G+C) herpesvirus subgroups. The production of excess thymidylate by a virus thymidylate synthase in cells infected with an A+T-rich herpesvirus would provide one plausible source of biased mutations by the virus-encoded replicative enzymes, which we have previously suggested as the likely general cause of differences in the mean nucleotide compositions of herpesvirus genomes.

Amino Acid Sequence↗
PubMed1986

Organization of the thymidylate synthase gene of herpesvirus saimiri.

Herpesvirus saimiri codes, unlike most other herpesviruses, for a thymidylate synthase (TS). The TS gene of herpesvirus saimiri is unusual in structure and regulation of expression. It is transcribed into a nonspliced mRNA of 2,190 nucleotides. The single open reading frame of the viral TS gene, instructing a polypeptide of 33.5 kilodaltons, has extensive sequence homology with the corresponding TS coding sequences of human cells and of various procaryotes; the putative polypeptide derived from the nucleotide sequence of the herpesvirus saimiri TS gene is 70% identical with the human enzyme. The untranslated regions of the herpesvirus saimiri TS gene do not share homology with the other characterized eucaryotic or bacterial TS genes. The 5' untranslated sequence has 22 ATG triplets shortly followed by stop codons. The herpesvirus saimiri TS gene, which may be weakly transcribed during immediate early and early times of virus replication, is maximally expressed at the late phase. Various parameters suggest that the TS gene has been acquired in virus evolution by an ancestral herpesvirus from the cellular genome.

Amino Acid Sequence↗
PubMed1985

Benzodiazepines--current safety issues.

Benzodiazepines are relatively safe compounds. They do, however, have an adverse effect on psychomotor and cognitive functions. A variety of behavioural and mood disturbances have been reported, including increased hostility, depression, antisocial behaviour, paranoid ideation, and suicidal tendencies. Benzodiazepines may produce pharmacological dependence in therapeutic dosage. The typical pattern of a drug dependence syndrome is rare. Dependence is primarily manifested by an abstinence syndrome occurring after the dose of the drug is reduced or treatment is stopped. The problems of distinguishing between the abstinence syndrome and anxiety are highlighted. Withdrawing a patient from benzodiazepines is discussed, as well as the management of the withdrawal syndrome.

Anti-Anxiety Agents↗
PubMed1985

Terminal repetitive sequences in herpesvirus saimiri virion DNA.

The H-DNA repeat unit of Herpesvirus saimiri strain 11 was cloned in plasmid vector pAGO, and the nucleotide sequence was determined by the dideoxy chain termination method. One unit of repetitive DNA has 1,444 base pairs with 70.8% G+C content. The structural features of repeat DNA sequences at the termini of intact virion M-DNA (160 kilobases) and orientation of reiterated DNA were analyzed by radioactive end labeling of M-DNA, followed by cleavage of the end fragments with restriction endonucleases. The termini appeared to be blunt ended with a 5'-phosphate group, probably generated during encapsidation by cleavage in the immediate vicinity of the single ApaI recognition site in the H-DNA repeat unit. The sequence did not reveal sizeable open reading frames, the longest hypothetical peptide from H-DNA being 85 amino acids. There was no evidence for an mRNA promoter or terminator element, and H-DNA-specific transcription could not be found in productively infected cells.

Animals↗
PubMed1984

Immediate-early transcription of Herpesvirus saimiri.

Transcription of Herpesvirus saimiri was characterized during the initial phases of productive infection by Northern blot analyses and hybridizations of radioactive cDNA with cloned fragments of virion L-DNA. Under conditions of immediate-early transcription, e.g., blocking of viral protein synthesis by cycloheximide, a single cytoplasmic polyadenylated viral RNA of 2.7 kilobases was found in infected cells. The sequence coding for this RNA was between map units 0.89 and 0.93; it was transcribed from right to left in prototype arrangement of M-DNA. The immediate-early mRNA of lytically infected cells appeared to be very similar, if not identical, to the single viral RNA species found in lymphoid cells transformed by H. saimiri.

Animals↗
PubMed1983

Cloning of Herpesvirus saimiri DNA fragments representing the entire L-region of the genome.

Purified particles of Herpesvirus saimiri, a potent tumor-eliciting virus of primates, contain genomic DNA molecules (145-170 kb) consisting of a unique L-DNA region (112 kb) which is flanked by variable stretches of repetitive sequences (H-DNA). Restriction fragments representing the entire L-DNA of H. saimiri strain No. 11 were cloned in plasmid and bacteriophage vectors. The internal fragments of L-DNA generated by the enzymes EcoRI and KpnI were inserted into plasmid pACYC184, cosmid pJC81, or bacteriophage lambda derivative Charon 4A. The terminal parts of L-DNA, including the junctions between repetitive DNA and unique sequences, were cloned between the cleavage sites for KpnI and SmaI in the plasmid vector pWD7, which was constructed for this purpose. Molecular cloning allowed us to confirm and modify, in part, the existing cleavage maps of H. saimiri DNA. It provides a basis for future studies on virus replication and oncogenic transformation.

Bacteriophage lambda↗
PubMed1983

Structural proteins of Herpesvirus saimiri.

Herpesvirus saimiri particles were purified from productively infected owl monkey kidney cell cultures, and the virion polypeptides were analyzed by polyacrylamide gel electrophoresis. A total of 21 predominant proteins were found in lysates of H. saimiri 11 particles by Coomassie blue staining or by [35S]methionine labeling and autoradiography; all proteins were between 160,000 and 12,000 daltons in size. They are most probably virion constituents, as most of them were precipitated by immune sera, and no dominant proteins of equivalent sizes were found in mock-infected cultures. Four glycoproteins (gp 155/160, gp 128, gp 84/90, gp 55) and three polypeptides that appeared not to be glycosylated (p71, p35, p28) were assigned to the envelope or matrix of virions, whereas at least four phosphoproteins (pp132, pp118, pp55, pp13) and ten polypeptides without apparent secondary modification (p155/160, p106, p96, p67, p53, p36, p32, p15, p14, p12) were found in the nucleocapsid fraction. Analysis of virion proteins from different H. saimiri strains did not reveal appreciable differences in the migration behavior of most polypeptides, including all glycoproteins; however, determination of a strain-specific size pattern was possible for three of four phosphoproteins. The overall similarity in protein architecture of H. saimiri strains obviously does not reflect the variability in biology, such as oncogenic properties. In comparison, DNA sequence divergences appear to remain a better taxonomic criterion for strain distinction.

Capsid↗
PubMed1983

Virus-specific transcription in a Herpesvirus saimiri-transformed lymphoid tumor cell line.

Herpesvirus saimiri-transformed lymphoid tumor cell lines contain nonintegrated covalently closed circular viral DNA molecules in high multiplicity. One of those cell lines, 1670, carries large viral DNA circles (202 kilobase pairs) with two stretches of repetitive DNA (70.8% G + C) that are interspersed between two segments of unique DNA (36% G + C). Since it was not known if there is any viral gene expression in H. saimiri-transformed cells, we initiated a study of transcription in cell line 1670. cDNA was generated by reverse transcription of cellular RNA and hybridized with cloned virion DNA fragments. The experiments indicated that appreciable transcription is restricted to a single segment of unique DNA. This sequence is present once only in the circular viral DNA and corresponds to unique DNA between map units 0.89 and 0.93 of virion DNA. By Northern blot hybridizations with labeled cloned probes of virion unique DNA, one predominant virus-specific polyadenylated transcript of, at most, 2.7 kilo-bases could be detected in tumor cell line 1670. The direction of transcription was determined by hybridization with randomly primed cDNA and, in parallel, with oligodeoxythymidylate-primed cDNA probes. Apparently, the patterns of virus-specific RNA synthesis in the H. saimiri-transformed cells are clearly distinct from the transcription program in other herpesvirus transformation systems analyzed before.

Animals↗
PubMed1978

Masking of protein antigen by modification of amino groups with carbobenzoxychloride (benzyl chloroformate) and demasking by treatment with nonspecific protease.

Cryostat sections of various substrates were treated with carbobenzoxychloride in acetone to modify antigens. By applying specific fluorescent antibodies, it could be shown that the antigenic determinants of rabbit gamma-globulin and bovine insulin were totally masked. The antigenicity of ACTH was markedly reduced, whereas the polysaccharide antigens of Salmonella typhimurium were only partially masked. After masking, antigenicity could be restored by treatment with nonspecific protease. The reversible protection of amino groups by carbobenzoxychloride may be a way to preserve protein antigens during embedding in plastics, as such materials also bind to amino groups, blocking the antigenicity of proteins.

Acetone↗
PubMed1977

Quantity of antibody synthesized in a single cell during the primary immune response.

Following immunization of mice with SRBC the kinetics of antibody synthesis by individual immunocompetent cells during the primary immune response were investigated. The diameter of the average hemolytic plaque using a modified Jerne plaquing technique, was taken to be an estimate of the antibody production by a single cell. We found an increase, followed by a decrease, of the average plaque diameter during the primary immune response. The increase of average plaque diameters is probably due to the raised rate of synthesis of antibody molecules. This increase can be accelerated by adjuvants. The decrease late in the primary immune response could be explained by an internally regulated switch from IgM to IgG antibody synthesis. The results are consistent with the mathematical approach of HELLWIG (1,2).

Adjuvants, Immunologic↗
PubMedDate not supplied

Detection of abundantly transcribed genes and gene translocation in human immunodeficiency virus-associated non-Hodgkin's lymphoma.

Several novel, differentially transcribed genes were identified in one centroblastic and one immunoblastic HIV-associated B-cell non-Hodgkin's lymphoma (B-NHL) by subtractive cloning. In both lymphomas, we detected an upregulated transcription of several mitochondrial genes. In the centroblastic B-NHL, we found a high level transcription of nuclear genes including the interferon-inducible gene (INF-ind), the immunoglobulin light chain gene (IgL), the set oncogene, and several unknown genes. The data obtained on upregulated expression of the genes in human B-NHL of HIV-infected patients considerably overlap with those obtained earlier for the B-NHL of simian immunodeficiency virus-infected monkeys. In the centroblastic lymphoma, one transcript revealed a fusion of the 3'-untranslated region of the set gene and the C-terminal region of the IgL gene. This chimeric sequence was confirmed by a site-directed polymerase chain reaction performed with total cDNA and genomic DNA. The expected amplification product was obtained in both cases pointing to a genomic rearrangement. The IgL-set fusion sequence was not found in cDNA preparations and genomic DNA of the immunoblastic HIV-associated B-NHL. Further studies are necessary to determine whether these genes contribute to lymphoma development or can be used as therapeutic targets.

3' Untranslated Regions↗