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Biomedical subjects

J B Clements

Publications and source records attributed to J B Clements.

At least 73 records · Page 4Linked to original sources
PubMed1980

Temporal regulation of herpes simplex virus type 2 transcription and characterization of virus immediate early mRNA's.

Nuclear and cytoplasmic virus RNAs, synthesized in cells infected with herpes simplex virus type 2 at early and late times post-infection, and in the continuous presence of the protein synthesis inhibitor cycloheximide (immediate early), have been analyzed by blot hybridization to virus DNA fragments generated by Bam HI and Eco RI restriction endonucleases. Polyadenylated immediate early mRNAs were separated on denaturing gels containing CH3HgOH giving three virus-specific mRNA bands of estimated sizes 4.7, 3.4 and 1.75 kb, and these have been mapped to five discrete regions of the genome. The polypeptides produced by in vitro translation of the HSV-2 immediate early mRNA's have been identified. Orientations of immediate early mRNA's on the virus genome have been determined by mapping cDNAs complementary to the 3'termini of the mRNAs.

Animals↗
PubMed1979

Hybrid plasmids containing an active thymidine kinase gene of Herpes simplex virus 1.

The gene for the thymidine kinase (TK) of Herpes simplex virus type 1 (HSV-1) is located in the KpnI m and BamHI p fragments of the genome (Wigler et al., Cell 11, 223-232 (1977)). These fragments have been inserted into the EcoRI and BamHI sites, respectively, of plasmid pBR322, and propagated in E.coli. The TK gene contained in the recombinant plasmids was shown to be biologically active when introduced into TK- mouse L cells. Detailed restriction site maps of the BamHI p fragment have been constructed and the approximate location of the TK gene has been determined. Mouse cells transformed with cloned HSV-1 tk+ DNA produced HSV-1-specific thymidine kinase; superinfection with HSV-1 tk- virus increased the level of TK activity tenfold, suggesting that the BamHI p sequences present in transformed cells respond to virus-encoded regulatory gene product(s).

Base Sequence↗
PubMed1979

Orientation of herpes simplex virus type 1 immediate early mRNA's.

We have determined the orientation of 4 immediate early (IE) mRNA's on the herpes simplex virus type 1 genome by mapping cDNA's complementary to the 3'-termini of messages. These IE mRNA's are transcribed by a pre-existing cell RNA polymerase, and we propose a model which allows their synthesis from a circular template using a single virus promoter region. The promoter region, which is located in the two repetitive DNA regions which flank the short unique region of the virus genome, may serve to initiate bidirectional transcription of these IE mRNA's.

Base Sequence↗
PubMed1979

Separation and characterization of herpes simplex virus type 1 immediate-early mRNA's.

Polyadenylated immediate-early transcripts of herpes simplex virus type 1, made in BHK cells infected and maintained in the presence of cycloheximide, have been separated on denaturing agarose gels containing methyl mercuric hydroxide. Three virus-specific mRNA bands of estimated sizes 4.7, 3.0, and 2.0 kilobases (kb) were detected, and these mRNA's were mapped on the virus genome and also used to direct protein synthesis in vitro. The 4.7- and 3.0-kb mRNA's hybridized predominantly to certain DNA fragments which are located in the short and long repetitive regions of the genome, respectively, whereas the 2.0-kb mRNA's mapped to three discrete regions of the virus DNA. In vitro translation of these separated mRNA size classes indicated that the 3.0-kb mRNA specified the synthesis of virus polypeptide Vmw 110, whereas the 2.0-kb mRNA's specified Vmw 68, 63, and 12. The synthesis of small amounts of Vmw 175 was specified by the 4.7-kb mRNA. In contrast with the mRNA's which specify these other immediate-early polypeptides, that specifying Vmw 12 is much larger than required for its coding sequences.

Animals↗
PubMed1978

Virus transcript mapping studies in cells infected with temperature-sensitive mutants of herpes simples virus type 1.

Nuclear and cytoplastic transcripts, synthesized in cells infected with six DNA-negative temperature-sensitive (ts) mutants of HSV-1 (ts B, ts D, ts E, ts K, ts S and ts T) under non-permissive conditions, were isolated and hybridized to unlabelled fragments of HSV-1 DNA, generated by restriction endonuclease digestion and immobilized on to nitrocellulose membranes by the method of Southern (1975). In this way it has been possible to map those regions of the HSV-1 genome represented by stable transcrips in cells infected with these mutants and compare them with those regions transcribed in cells infected with the wild-type virus at early and late times post infection (before and after viral DNA replication) and in the presence of DNA- and protein-synthesis inhibitors. Viral transcription in ts D, ts T and ts K-infected cells is restricted, the patterns of hybridization being similar, but not identical to that observed with immediate early RNA. Since these three mutants fall into two complementation groups, these experiments suggest that at least two viral products are required for the switch-on of early transcripts. In contrast, transcript mapping with the other early mutants (ts B, ts E and ts S) has shown a much less restricted transcriptional pattern, the pattern obtained resembling that with early, rather than late RNA.

Cell Transformation, Viral↗
PubMed1976

Renovascular hypertension from renal artery compression by congenital bands.

Renal artery compression by fibromuscular bands containing sympathetic nerves and ganglia was encountered in 3 of 75 patients with renovascular hypertension. The hypertension was successfully managed by resection of the bands. The absence of mortality and morbidity dictates that the "stenotic" area of the renal artery be explored, especially in children and adults with minimal angiographic evidence of visceral atherosclerosis, before proceeding with a bypass graft to the renal artery.

Adult↗
PubMed1976

Analysis of herpesvirus DNA substructure by means of restriction endonucleases.

The mol. wt. and molar ratios of the Hind III and Hpa I fragments of HSV-1 DNA and the Eco RI fragments of HSV-2 DNA have been determined. Results obtained suggest that DNA isolated from both HSV-1 and HSV-2 consists of molecules with four different sequence arrangements which are present in similar amounts. Our explanation of the cleavage patterns of these four genome arrangements with the different restriction enzymes is presented. Some of the possible implications of these four genome arrangements for genetic recombination are discussed.

Base Sequence↗
PubMed1976

Virus specified enzyme activity and RNA species in herpes simplex virus type 1 transformed mouse cells.

LMTK-cells infected with u.v.-irradiated herpes simplex virus type 1 have been selected for the presence of the enzyme thymidine kinase. These cells have an altered morphology compared to the control cells and contain herpes-specific antigens in their cytoplasm. The thymidine kinase activity present in these cells has been shown, on the basis of a number of biochemical properties, to be identical to the herpes virus specified deoxypyrimidine kinase found during lytic infection of this virus. In addition it has been possible to detect herpes simplex-specific RNA sequences in the transformed cells and this occurs in both the polyadenylated and non-polyadenylated cytoplasmic and nuclear fractions.

Animals↗
PubMed1976

A partial denaturation map of herpes simplex virus type 1 DNA: evidence for inversions of the unique DNA regions.

Partial denaturation maps of 30 HSV-I DNA molecules have been obtained using a procedure designed to avoid possible hydrolysis of the DNA at alkalilabile bonds. From the denaturation pattern of the long unique DNA region these molecules were divided into two groups comprised of 16 and 14 molecules. Histogram plots relating the precentage denaturation to position on the DNA for these two groups were aligned in a manner appropriate to the HSV-I genome model. It was apparent that these groups had the orientation of the long region inverted with respect to each other. Similarly, from the denaturation maps of the short unique region, the molecules were divided into two groups each comprising 15 molecules. Alignment of the histogram plots of these groups indicated that the orientation of the short region was inverted in one group relative to the other. These partial denaturation data confirm the presence of four HSV-I genome arrangements resulting from the possible combinations of inversions of the two unique DNA regions.

DNA, Viral↗
PubMed1975

Process of infection with bacteriophage phiX174. XXXVII. RNA metabolism in phiX174-infected cells.

The RNA produced in vivo from bacteriophage phiX174 DNA has been analyzed by polyacrylamide-agarose gel electrophoresis and sedimentation in dimethyl sulfoxide gradients, and the results of Hayashi and Hayashi (1970) have been confirmed and extended. An efficient procedure for recovery of RNA from gels, followed by a hybridization assay, has indicated the presence in infected cells of 18 distinct RNA species with sizes up to and greater than the unit (viral) length. The sizes of phiX mRNA's were similar irrespective of whether material was analyzed on gels or in dimethyl sulfoxide gradients. When virus-induced RNA was detected by a double-label method, seven additional low-molecular weight species were observed on gels and the resolution of dimethyl sulfoxide gradients was enhanced. The present results lend support to aspects of the model of Hayashi and Hayashi (1970) for the generation of these discrete mRNA species; an alternative model is also discussed.

Coliphages↗
PubMed1974

Class of phi chi 174 mutants relatively deficient in synthesis of viral RNA.

Nonpermissive cells infected with phiX174 gene D amber mutants synthesized some sixfold less viral RNA than permissive cells. The decrease was unaffected by increasing the multiplicity of infection and was a consequence of an overall decrease in all viral RNA species. It is suggested that the gene D product may function in replicative form DNA unwinding to expose the template for transcription.

Coliphages↗