bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Host Cell Ribosomal Ribonucleic Acid Methylation by Foot-and-Mouth Disease Virus
Authors: Ascione Richard , Vande Woude George F.
Published: January 2020

A study of protein and ribonucleic acid (RNA) synthesis in cells infected by foot-and-mouth disease virus has indicated possible mechanisms of viral control over host cell metabolism. Foot-and-mouth disease virus infection of baby hamster kidney cells resulted in 50% inhibition of host cell protein synthesis at 180 min postinfection. A viral-induced interference with host cell RNA methylation was observed to be more rapidly inhibited than protein synthesis. To determine the nature of methylation inhibition, the kinetics of several host cell methylated RNA species were examined subsequent to virus infection. Data from sucrose zonal centrifugation and methylated albumin kieselguhr chromatography showed that methylation of nuclear RNA was inhibited 50% at 60 min postinfection. Inhibition of nuclear ribosomal RNA precursors and formation of nascent ribosomes correlated with inhibition kinetics of nuclear RNA methylation. It is suggested that the viral interference with the host nuclear RNA methylation is directly responsible for the observed loss of nascent ribosome formation. Moreover, early in the infectious cycle, methylation inhibition of host cell RNA could, in part, account for the cessation of host protein synthesis.
Comparison of Four Horse Herpesviruses
Authors: Plummer G. , Bowling C. P. , Goodheart C. R.
Published: January 2020

Four equine herpesviruses (equine abortion virus, equine herpesvirus types 2 and 3, and equine cytomegalovirus) were compared. The equine abortion virus did not cross-neutralize with any of the other viruses, but the other three did show varying degrees of cross-neutralization among themselves. Equine abortion virus grew more quickly in tissue cultures than did the others, and attained higher titers of infectivity in the culture fluid; it also formed plaques in a wider range of tissue culture species, although the other three were not specific for one tissue culture system only, in that they would multiply in rabbit and cat kidney cultures. The densities of the deoxyribonucleic acids of all four viruses were in the range 1.716 to 1.717 g/ml (a guanine plus cytosine content of 57 to 58%). Taxonomic separation, as a distinct serotype, of equine abortion virus from the other herpesviruses seems to be justified. The other three are closely related to one another. They should perhaps be regarded as separate viruses and termed horse herpesviruses types 2, 3, and 4, although an alternative view would be to regard them as variants of a single virus type. The question of whether types 2, 3, and 4, or any other herpesviruses, should be placed in a phylogenetically distinct subgroup, known as cytomegaloviruses, is a moot point.
Control of Gene Function in Bacteriophage T4
Authors: Sauerbier Walter , Puck Stirling M. , Bräutigam Alan R. , Hirsch-Kauffmann Monica
Published: January 2020

Deoxyribonucleic acid (DNA) synthesis in T4rII-infected, lambda-lysogenic strains of
Escherichia coli
proceeds with one-half the rate of T4 wild-infected bacteria and stops 16 min after infection at 37 C. The rates of ribonucleic acid (RNA) synthesis, however, are the same with T4rII and T4 wild. The turnover of pulse-labeled RNA is slow in K strains (half-lives 10 to 20 min) as compared with B strains (half-lives 2.5 to 6 min). Lambda-lysogeny increases the apparent messenger (m) RNA half-lives in pulse-chase experiments. The shutoff of host RNA synthesis in T4rII infected K(λ) is incomplete. Moreover, the preferential transcription of T4 DNA ceases 13 min after infection, and transcription of host and prophage λ DNA is resumed. The T4 RNA synthesized in rII-infected K(λ) contains no late T4 mRNA. The early portion of the T4 genome, however, is transcribed completely. The T4-induced early modification of bacterial RNA polymerase does occur. Resumption of host DNA transcription at 13 min after infection is not associated with a reversal of the above polymerase modification. It is concluded that in lambdalysogenic bacteria T4rII infections are abortive because RNA polymerase is prevented from transcribing late T4 genes.
Restoration by Chloramphenicol of Bacteriophage Production in
Escherichia coli
B Infected with a Ligase-Deficient Amber Mutant
Authors: Kozinski Andrzej W. , Mitchell Marilyn
Published: January 2020

The addition of chloramphenicol (CM) 5 min after infection of the nonpermissive host
Escherichia coli
B with the ligase-negative T4 amber, T4 AmH39X, allowed replication of parental deoxyribonucleic acid (DNA) and the production of high-molecular-weight progeny DNA, composed mostly of subunits with a D
2
/D
1
of 0.6. When CM was removed after the accumulation of a large pool of this DNA, most of the infected bacteria were able to produce viable progeny phage, with an average yield of approximately 15 bacteriophage per bacterium. This phenomenon is called CM rescue of the ligase-negative T4 Am. CsCl and sucrose gradient analyses showed both the resulting phage and DNA extracted from them to be similar to the phage and DNA produced on the permissive host. The total transfer of the parental label to progeny phages was as high as 20%. In contrast, in bacteria not treated with CM or in bacteria to which CM was added after phage-coded nucleases had already been synthesized, both parental and progeny (newly synthesized) DNA was composed of very short fragments. Phage which are produced under conditions other than those of CM rescue are dead, light in CsCl, and contain only very short fragments of DNA. Parent-to-progeny transfer in this case is below 1%. When light radio-active parental DNA was used to infect heavy bacteria, DNA replicating in the CM rescue conditions assumed only a hybrid density. After removal of CM and maturation, the parental DNA was incorporated into progeny molecules in fragments constituting approximately 7 to 10% of its mass. This pattern of distribution is essentially what is observed in similar experiments in the permissive host. The role of ligase as an enzyme which compensates for the lethal action of phage-coded nuclease and which is stringently required for the repair of single-stranded nicks is emphasized. The possibility of specific sites for a unique cutting enzyme is discussed in connection with the hypothesis of a circularly permuted assembly of sets.
Inheritance of Susceptibility to Friend Mouse Leukemia Virus
Authors: Odaka Takeshi , Matsukura Michio
Published: January 2020

Two newly established mouse strains which are congenic with standard inbred strains were used for the study of the locus
Fv
which controls the susceptibility to Friend leukemia virus in mice. A strain in each congenic pair shares the major histocompatibility gene with the corresponding partner strain but differs from the latter in the
Fv
locus. Mice with
Fv
r
/
Fv
r
genotype (DDD-
Fv
r
, C57BL/6) do not develop marked spleen enlargement upon virus challenge, whereas spleens of mice with
Fv
s
/
Fv
s
genotype (DDD, C57BL/6-
Fv
s
) become large even with a virus inoculum 1/10
3
to 1/10
5
times that used for the resistant strains. Mice of each strain were heavily irradiated, inoculated with bone marrow cells taken from either syngenic or corresponding congenic mice, and challenged later with the leukemia virus. When
Fv
s
/
Fv
s
mice had been restored with bone marrow cells taken from
Fv
r
/
Fv
r
mice, the spleens remained small after the virus inoculation. In contrast,
Fv
r
/
Fv
r
mice receiving
Fv
s
/
Fv
s
cells responded to the virus with marked spleen enlargement. In the enlarged spleens of the C57BL/6 mice which do not otherwise allow the virus multiplication, a considerable amount of infectious virus was found. The altered response seems to be due to repopulation of destroyed tissues by the transplanted bone marrow cells. It is concluded that the locus
Fv
is expressed on hemopoietic cells, and cells derived from bone marrow play a predominant role in the development of splenomegaly by Friend leukemia virus.
Synthesis of Viral-Specific Ribonucleic Acid in Rubella Virus-Infected Cells
Authors: Wong Ken T. , Robinson William S. , Merigan Thomas C.
Published: January 2020

Monolayers of BHK-21/W1-2 cells were pulsed with
3
H-uridine at different times after infection with rubella virus, and viral-specific cytoplasmic ribonucleic acid species were demonstrated.
Characterization of bacteriophage N3 DNA
Authors: Filipska E S , Moynet D J , DeFilippes F M
Published: January 2020

The DNA from Haemophilus influenzae temperate phage N3 was characterized by centrifugation and by electrophoresis after nuclease digestion. The double-stranded DNA, with a mass of 25.8 X 10(6) daltons, had single-strand cohesive ends. Strand association through cohesion was reduced by heat and removed by S1 nuclease digestion. N3 DNA contained five EcoRI, one KpnI, two SacI, six XbaI, and four XhoI cleavage sites. The cohesive end segments were identified by heating the digests before electrophoresis. This was the first step in the construction of the physical maps of this DNA.
DNA synthesis and template activity in a mutant of polyoma virus with altered expression of late viral proteins
Authors: Blackburn C , Hare J D
Published: January 2020

The 3049 strain of polyoma virus overproduces late RNA and proteins. The synthesis and accumulation of virus DNA was measured in cells infected with 3049 and a wild-type virus, lpS, to assess the possible role of gene dosage in this phenomenon. The rate of incorporation of [3H]thymidine into the DNA of 3049 and lpS virus was shown to be identical. The number of genome copies per cell, determined by DNA-DNA reassociation kinetics, was found to be similar in either whole cell or Hirt extracts of cells infected with the two viruses. Viral transcription complexes were isolated by Sarkosyl extraction, and the specific transcriptional activity was measured by incorporation of [3H]UTP. The incorporation of [3H]UTP and the DNA content of transcription complexes were indistinguishable. These results suggest that overproduction of late RNA (and protein) by the 3049 virus is not due to either an increased number of viral genomes per cell or an increased fraction of genomes involved in transcription. These and other data (unpublished) support the conclusion that the altered phenotype is due to a posttranscriptional mechanism.
BK virus-transformed inbred hamster brain cells. I. Status of the viral DNA and the association of BK virus early antigens with purified plasma membranes
Authors: Beth E , Giraldo G , Schmidt-Ullrich R , Pater M M , Pater A , di Mayorca G
Published: January 2020

Inbred LSH hamster brain cells were transformed in vitro by the GS strain of BK virus (BKV), and transplantable tumors classified as undifferentiated glioblastomas were induced in the syngeneic host. The viral status in the transformed cells, designated LSH-BR-BK, was established. About 46 genome equivalents per cell of viral DNA was detected, with the majority of sequences in a free form. The transformed cells expressed large quantities of tumor (T) antigen as well as surface (S) antigen as demonstrated by indirect immunofluorescence. Sixty-three percent of tumor-bearing hamsters produced high-titer antibodies against T, whereas 3 of 14 (21%) hamsters also produced antibodies against the BKV-specific S antigen. Furthermore, the relatedness of BKV early gene products, including T, S, and tumor-specific transplantation antigen, was established by the production of a rabbit antiserum against highly purified plasma membranes of LSH-BR-BK cells and by the induction of a BKV-specific tumor-specific transplantation antigen response by these plasma membranes in the syngeneic host.
Genetic and amber fragment maps of genes 46 and 47 of bacteriophage T4D
Authors: Wiberg J S , Cardillo T S , Mickelson C
Published: January 2020

We constructed genetic recombinational maps of genes 46 and 47 by using five amber mutants in gene 46, nine amber mutants in gene 47, and two-factor crosses. Two different amber fragments in gene 46 and three different amber fragments in gene 47 were detected on polyacrylamide slab gels in the presence of sodium dodecyl sulfate. The genetic maps agreed with the amber fragment maps; taken together, the data oriented all of the sites in both genes with respect to each other. Given the relative map positions of genes 46 and 47 determined genetically by Epstein et al. (Cold Spring Harbor Symp. Quant. Biol. 28:375-394, 1963), our results extend and reinforce the work of Hercules and Sauerbier (J. Virol. 12: 872-881, 1973) and that of Minner and Bernstein (J. Gen. Virol. 31:277-280, 1976), which indicated that the direction of transcription and translation of these genes if counterclockwise on the T4 genetic map (i.e., from gene 47 toward gene 46).
Varicella-zoster virus vaccine DNA differs from the parental virus DNA
Authors: Ecker J R , Hyman R W
Published: January 2020

The DNAs of a varicella-zoster virus vaccine and its parental virus were compared by CsCl buoyant density centrifugation and restriction enzyme cleavage analysis. The varicella-zoster virus vaccine DNA showed a heterogeneous buoyant profile and altered restriction enzyme cleavage patterns. These changed properties are probably the result of the accumulation of virus containing defective varicella-zoster virus DNA during extensive cell culture passage of the vaccine virus.
Insertion of influenza M protein into the viral lipid bilayer and localization of site of insertion
Authors: Gregoriades A , Frangione B
Published: January 2020

Recent studies with isolated M protein from influenza virus have shown that the protein has a high affinity for lipid. The ability of M to partition into lipid vesicles merely by shaking vesicles and M together is suggestive evidence that the protein could be interacting with the lipid in the virus particle. A more direct analysis was carried our here to determine whether M is in contact with the viral lipid in situ, by using the photoactivatable hydrophobic probe, pyrenesulfonyl azide. Covalent linkage of this probe to M indicated that a segment of M residues with in the virus membrane in contact with the lipid bilayer. M inserted into lipid vesicles at two locations on the molecule. A major insertion into lipid occurred in the middle of the molecule where a large cluster of 20 hydrophobic and neutral amino acids occurs. A second insertion occurred approximately one fourth in from the amino terminus, where a smaller segment of 13 uncharged amino acids is found. Confirmation that M inserted into lipid at these locations came also from results with cyanogen bromide fragments of M. Of the 12 to 13 fragments produced, 3 specifically bound to lipid vesicles. These were the first, second, and third contiguous segments beginnings at the amino terminus and containing the two hydrophobic areas noted above.
Coliphage 186 Replication is delayed when the host cell is UV irradiated before infection
Authors: Hooper I , Woods W H , Egan B
Published: January 2020

In contrast to results with injections by lambda and P2, the latent period for infection by coliphage 186 is extended when the host cell is UV irradiated before infection. We find that 186 replication is significantly delayed in such a cell, even though the phage itself has not been irradiated. In contrast, replication of the closely related phage P2 under the same conditions is not affected.
Proteins Specified by bovine herpesvirus 1 (infectious bovine rhinotracheitis virus)
Authors: Misra V , Blumenthal R M , Babiuk L A
Published: January 2020

An electrophoretic analysis of radioactively labeled, purified, "empty" and DNA-containing infectious bovine rhinotracheitis virions revealed the presence of 25 to 33 structural (virion) polypeptides. A total of 11 of these polypeptides could be labeled with [3H]glucosamine and were identified as glycoproteins. In addition to the 25 structural polypeptides, infectious bovine rhinotracheitis virus infected cells also contained at least 15 nonstructural (nonvirion) polypeptides that were not present in purified virions. Expression of the viral polypeptides in infected cells was controlled temporally. Thus, most viral polypeptides could be categorized as "alpha" (immediate early), "beta" (early), or "gamma" (late) on the basis of their order of appearance in infected cells and whether their syntheses were dependent upon prior viral protein or DNA synthesis. None of the glycoproteins belongs to the alpha class, although at least one (GVP11) was synthesized in the absence of viral DNA synthesis. Serum from a cow in which infectious bovine rhinotracheitis virus lesions were reactivated by dexamethasone precipitated both structural and nonstructural polypeptides.
Isolation and characterization of a new bacteriophage, Cp-1, infecting Streptococcus pneumoniae
Authors: Ronda C , López R , García E
Published: January 2020

Several pneumococcal phages showing a morphology completely different from those of all other previously found pneumococcal bacteriophages have been isolated. Bacteriophage Cp-1, one of the phages isolated, showed an irregular hexagonal structure and a short tail of 20 nm. The virion density was 1.46 g/cm3. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of nine polypeptides. The polypeptide showing a molecular weight of 39,000 accounted for more than the 90% of the total protein. The nucleic acid of Cp-1 was linear, double-stranded DNA with a mean length of 6.3 microns and a guanine-plus-cytosine content of 41%; its buoyant density was 1.699 and 1.422 g/cm3 in CsCl and CS2SO4, respectively. Its sedimentation coefficient (S20,w) was 19S. Cp-1 DNA showed a remarkable resistance to a large number of restriction endonucleases. A total of 12 fragments, ranging in molecular weight from 1.3 X 10(6) to 0.09 X 10(6), were produced by AluI, two fragments (molecular weight, 5.5 X 10(6) and 0.9 X 10(6)) were generated by HindIII, and two fragments (molecular weight, 6.0 X 10(6) and 5.7 X 10(6)) were produced by HaeIII. The easy visualization of th plaques produced by Cp-1, the small size of Cp-1 DNA (12 X 10(6) daltons), and other biological and physiochemical properties make this phage potentially useful for genetic studies.
Theiler's murine encephalomyelitis virus group includes two distinct genetic subgroups that differ pathologically and biologically
Authors: Lorch Y , Friedmann A , Lipton H L , Kotler M
Published: January 2020

The intracellular development and RNA composition of Theiler's murine encephalomyelitis virus (TMEV) isolates were determined by electron microscopy, sucrose gradient centrifugation, and RNase T1 fingerprinting. Replication of FA virus, a virulent strain of TMEV, was characterized by the appearance of viral crystalline arrays in the cytoplasm of infected cells. In contrast, cells infected with the less virulent isolates (WW, TO4, BeAn 8386, and Yale) showed no crystalline arrays; instead, virions were found to be arranged between two layers of membranes in the cytoplasm of infected cells. Analysis of the RNAs of TMEV isolates showed that the RNAs were single-stranded molecules having sedimentation coefficients of 35S. RNase T1 fingerprinting of TMEV RNA revealed that striking differences between the virulent and less virulent TMEV isolates existed. Moreover, base composition analysis of RNase T1-resistant oligonucleotides of two TMEV isolates which represented the two subgroups indicated that there were no substantial oligonucleotides common to both subgroups. Based on these findings and the known difference in virulence, we suggest that the TMEV group contains two genetically district subgroups of viruses.
Abelson virus-infected cells can exhibit restricted in vitro growth and low oncogenic potential
Authors: Whitlock C A , Witte O N
Published: January 2020

We have designed a method for growing bone marrow cells infected with Abelson murine leukemia virus which permits examination of target cell growth early after infection. This culture system increases the efficiency of target cell growth by favoring rapid growth of a mixed population of adherent cells in the primary culture. The nonadherent Abelson virus-infected cell populations expressed pre-B-cell differentiation markers characteristic of Abelson virus-transformed cells (mu-heavy chains of immunoglobulin M and terminal deoxynucleotidyltransferase). Early after infection, these cell populations exhibited restricted in vitro and in vivo growth properties which differed from those of an established Abelson virus-transformed cell line, 2M3. These included a marked dependency upon the adherent cell layer for growth and viability, a lower efficiency of agar colony formation, and a lower capacity for tumor production in syngeneic animals. Growth of the early populations could be maintained in the absence of the adherent cell layer by using conditioned medium from long-term adherent cell cultures established in the absence of viral infection. After passage of the populations for several weeks, the in vitro growth properties gradually shifted toward that of the 2M3 cell line. Twelve-week-old populations grew independently of the adherent cell layer and showed an increased efficiency of agar colony formation. These data indicate that many lymphoid target cells exhibit an intermediate transformed phenotype when infected with Abelson virus. Growth of these cells in culture is mediated via a synergistic interaction between intracellular expression of the viral transforming gene and an exogenous growth-promoting activity which can be provided by cultures of adherent bone marrow cells.
Late nonstructural 100,000- and 33,000-dalton proteins of adenovirus type 2. II. Immunological and protein chemical analysis
Authors: Gambke C , Deppert W
Published: January 2020

For an immunological analysis of the late adenovirus type 2 nonstructural 100,000-dalton (100K) and 33K proteins, we prepared antisera against sodium dodecyl sulfate-denatured, gel-purified 100K and 33K proteins. These antisera were tested for potential cross-reactivity, since according to a previous report (Axelrod, Virology 87:366--383, 1978) these two proteins exhibit extensive amino acid homologies. However, immunoprecipitations of 100K and 33K proteins, as well as a sensitive immune replica technique, did not reveal any immunological relationship between these proteins. Therefore, using fingerprint peptide analysis, we investigated the structural relationship between 100K and 33K proteins labeled with a 14C-amino acid mixture or with [14C]proline after digestion with trypsin. We detected only minor, if any, amino acid homologies, indicating that the 100K and 33K proteins are not structurally related.
Sizes of bacteriophage T4 early mRNA's separated by preparative polyacrylamide gel electrophoresis and identified by in vitro translation and by hybridization to recombinant T4 plasmids
Authors: Young E T , Menard R C
Published: January 2020

We determined the sized of specific T4 prereplicative nRNA's by preparative polyacrylamide gel electrophoresis, and we used the following two techniques to identify specific gene transcripts; cell-free protein synthesis accompanied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to distinguish T4 polypeptides and hybridization to recombinant plasmids containing T4 DNA of known genetic composition. In our first analysis, the use of nonsense and in-phase deletion mutants allowed unambiguous identification of the functional transcripts that encoded genes 32, rIIB, and rIIA. In addition, we identified the functional transcript that encoded genes 43, 45, 30, 39, and 52, the beta-glucosyl transferase gene, and the deletion 293 region. A single peak of mRNA activity that coded for gp43, gp39, gprIIA, beta-glucosyl transferase, and the polypeptide encoded in the deletion 293 region was present; the other polypeptides were encoded in multiple mRNA species, gp46 and gp32 were encoded by two mRNA's and gp52 and gprIIB were encoded by three nRNA's. By hybridizing fractionated, pulse-labeled early RNA to cloned restriction fragments of T4 DNA, we identified the same specific transcripts for genes 43, 52, and rIIB. In addition, a lower-molecular-weight RNA (presumably degraded nRNA) was present even in pulse-labeled RNA preparations. The distribution of pulse-labeled RNAs that hybridized to gene 39, gene 30, gene rIIA, gene 40 plus gene 41, and gene 42 plus the beta-glucosyl transferase gene indicated extensive degradation. We detected cotranscription of genes rIIA and rIIB by rehybridization of RNA first annealed to an rIIB plasmid and then eluted and annealed to an rIIA plasmid. The size distributions of normal and chloramphenicol-treated RNAs that hybridized to plasmids containing T4 immediate early gene 30, gene 39, gene 40 plus gene 41, and gene 42 plus the beta-glucosyl transferase gene were not significantly different.
Acyclovir-resistant mutants of herpes simplex virus type 1 express altered DNA polymerase or reduced acyclovir phosphorylating activities
Authors: Furman P A , Coen D M , St Clair M H , Schaffer P A
Published: January 2020

The biochemical properties of four acyclovir-resistant mutants are described. Two of these mutants, PAAr5 and BWr, specified nucleotidyl transferase (DNA polymerase) activities which were less sensitive to inhibition by acyclovir triphosphate than their wild-type counterparts. Another mutant, IUdRr, exhibited reduced ability to phosphorylate acyclovir. The fourth mutant, ACGr4, both induced an altered DNA polymerase and failed to phosphorylate appreciable amounts of acyclovir. BWr, a new acyclovir-resistant mutant derived from the Patton strain of herpes simplex virus type 1, induced a DNA polymerase resistant to inhibition by acyclovir triphosphate, but, unlike the polymerases induced by PAAr5 and ACGr4, still sensitive to phosphonoacetic acid. Resistance of BWr to acyclovir mapped close to the PAAr locus and was separable from mutations in the herpes simplex virus thymidine kinase gene by recombination analysis.
Modification of RNA polymerase from Escherichia coli by pre-early gene products of bacteriophage T5
Authors: McCorquodale D J , Chen C W , Joseph M K , Woychik R
Published: January 2020

RNA polymerase from cells of Escherichia coli infected with T5 were recovered as a complex with two pre-early phage-coded polypeptides, the 60,000-dalton product of gene A1 and a previously reported 11,000-dalton polypeptide. This RNA polymerase complex had altered transcriptional specificity, in that it transcribed pre-early genes less efficiently than it did early genes.
Activation and characterization of the reovirus transcriptase: genetic analysis
Authors: Drayna D , Fields B N
Published: January 2020

We studied the ability of chymotrypsin to activate the transcriptases of the three serotypes of reovirus. When we used conditions that reproducibly caused the activation of type 3 transcriptase by chymotrypsin alone, type 2 transcriptase was sometimes activated, and type 1 transcriptase was never activated. Using intertypic recombinants containing various combinations of genome segments from reovirus types 3 and 1, we showed that the M2 segment determined this difference. Biochemical experiments indicated that the digestion of reovirus type 1 by chromotrypsin was blocked at an intermediate stage in uncoating. We found conditions which reproducibly activated the transcriptases of all three serotypes. This allowed us to compare the biochemical properties of the three transcriptases. Although the monovalent cation preferences, divalent cation preferences and optima, and temperature optima of type 1, 2, and 3 transcriptases were indistinguishable, the pH activity curves were reproducibly different. The largest difference was between type 2 and 3 transcriptases; the pH optimum of type 2 transcriptase was lower than the pH optimum of type 3 transcriptase. Using intertypic recombinants containing various combinations of genome segments from reovirus types 2 and 3, we demonstrated that the L1 segment specified this difference.
Similarities and differences in the Fc-binding glycoprotein (gE) of herpes simplex virus types 1 and 2 and tentative mapping of the viral gene for this glycoprotein
Authors: Para M F , Goldstein L , Spear P G
Published: January 2020

We performed affinity chromatography and immunoprecipitation experiments to determine whether cells infected with herpes simplex virus type 2 (HSV-2) expressed a glycoprotein that was functionally and antigenically related to the HSV-1 Fc-binding glycoprotein designated gE. We found that a protein from extracts of HSV-2-infected HEp-2 cells bound specifically to an Fc affinity column and that the electrophoretic mobility of this protein in sodium dodecyl sulfate-acrylamide gels was slightly less than the mobility of HSV-1 gE. Immunoprecipitation experiments performed with an antiserum prepared against HSV-1 gE revealed that (i) extracts from HSV-2-infected cells contained a glycoprotein that was antigenically related to HSV-1 gE; (ii) the electrophoretic mobility of the HSV-2 gE was indistinguishable from the mobility of the HSV-2 Fc-binding protein; (iii) the antiserum reacted with both newly synthesized transient forms and stable fully processed forms of both HSV-1 gE and HSV-2 gE; and (iv) the transient and stable forms of HSV-2 gE all had lower electrophoretic mobilities than their HSV-1 counterparts. Electrophoretic analyses of gE precipitated from extracts of HEp-2 cells infected with two sets of HSV-1 x HSV-2 intertypic recombinant viruses suggested that the gene for gE is located at the right end of the HSV genome (0.85 to 0.97 map units) in the unique portion of the S component.
Spontaneous variation and synthesis in the U3 region of the long terminal repeat of an avian retrovirus
Authors: Shimotohno K , Temin H M
Published: January 2020

Recombinant DNA clones of a viral clone of spleen necrosis virus, an avian retrovirus, were found to have long terminal repeats of different sizes. The variation was in the U3 region of the long terminal repeats, and any one clone had U3 of the same size in both long terminal repeats. The U3 regions in the 5' and 3' long terminal repeat were shown both to be derived from the 3' long terminal repeat of parental virus DNA.
Analysis of human cytomegalovirus nucleoprotein complexes
Authors: St Jeor S , Hall C , McGaw C , Hall M
Published: January 2020

When chromatin was isolated from cells infected with human cytomegalovirus, the virus DNA remained with the chromatin fraction. If deproteinized virus DNA was added to either isolated nuclei or chromatin, the DNA was lost during the chromatin isolation. When isolated chromatin from cytomegalovirus-infected cells was banded in isopycnic metrizamide gradients, a single peak with a density of 1.18 g/cm3 was present. Analysis of this peak in isopycnic neutral CsCl gradients indicated that it contained both human cytomegalovirus and human embryonic lung cell DNAs. When infected nuclei were treated with micrococcal nuclease, 11S subunit particles which cosedimented with cell nucleosomes and contained virus DNA were isolated.
The double-stranded RNA genome segments of cytoplasmic polyhedrosis virus are independently transcribed
Authors: Smith R E , Furuichi Y
Published: January 2020

The in vitro transcription of the genome segments of insect cytoplasmic polyhedrosis virus was examined for a possible mechanism of coordinate control. Initiation of the first transcription cycle, primed by preincubation in the absence of CTP, was synchronous for all 10 viral genome segments. The time required for the completion of each genome transcript was proportional to the chain length, and all 10 mRNA's were synthesized in molar amounts inversely proportional to their molecular weights. The rate of chain elongation for all mRNA's was approximately 6 nucleotides per s. The combined results indicate that each of the viral genome segments is transcribed independently and suggest that RNA chain elongation, not initiation, is rate limiting for cytoplasmic polyhedrosis virus mRNA synthesis in vitro.
Plasmid pR386 renders Escherichia coli cells restrictive to the growth of bacteriophage T4 unf mutants
Authors: Herman R E , Snustad D P
Published: January 2020

The introduction of the F1 incompatibility group plasmid pR386 Tc into several common laboratory strains of Escherichia coli rendered them restrictive to the growth of bacteriophage T4 unf mutants, which are defective in unfolding the host genome. The growth inhibition was temperature dependent. The single mutant unf39 x 5 exhibited an efficiency of plating of less than 10(-8) at 27 degrees C. However, at 37 degrees C, complete growth inhibition occurred only when host DNA degradation was also absent.
Biochemical evidence of recombination within the unsegmented RNA genome of aphthovirus
Authors: King A M , McCahon D , Slade W R , Newman J W
Published: January 2020

Four different pairs of temperature-sensitive mutants, derived from the same strain of aphthovirus, were crossed by using an infectious center recombination test. Each parental mutant carried an unselected marker affecting the isoelectric point of a virus-coded polypeptide; progeny of the crosses, able to grow at the nonpermissive temperature, were screened for these unselected markers. Polypeptide charge was shown to be a stable, inheritable character, and three of the four crosses yielded genetic recombinants that possessed the polypeptide marker from both parents. Peptide fingerprinting and high-resolution isoelectric focusing of the polypeptides ruled out the explantation that these viruses were generated by mutation.
Morphogenesis of bacteriophage phi 29 of Bacillus subtilis: DNA-gp3 intermediate in in vivo and in vitro assembly
Authors: Bjornsti M A , Reilly B E , Anderson D L
Published: January 2020

The assembly of phage phi 29 occurs by a single pathway, and DNA-protein (DNA-gp3) has been shown to be an intermediate on the assembly pathway by a highly efficient in vitro complementation. At 30 degrees C, about one-half of the viral DNA synthesized was assembled into mature phage, and the absolute plating efficiency of phi 29 approached unity. DNA packaging at 45 degrees C was comparable to that at 30 degrees C, but the burst size was reduced by one-third. When cells infected with mutant ts3(132) at 30 degrees C to permit DNA synthesis were shifted to 45 degrees C before phage assembly, DNA synthesis ceased and no phage were produced. However, a variable amount of DNA packaging occurred. Superinfection by wild-type phage reinitiated ts3(132) DNA synthesis at 45 degrees C, and if native gp3 was covalently linked to this DNA during superinfection replication, it was effectively packaged and assembled. Treatment of the DNA-gp3 complex with trypsin prevented in vitro maturation of phi 29, although substantial DNA packaging occurred. A functional gp3 linked to the 5' termini of phi 29 DNA is a requirement for effective phage assembly in vivo and in vitro.
The leader sequence of the subgenomic mRNA's of Rous sarcoma virus is approximately 390 nucleotides
Authors: Hackett P B , Swanstrom R , Varmus H E , Bishop J M
Published: January 2020

The subgenomic mRNA's of Rous sarcoma virus share a common 5' leader sequence spliced from genomic RNA. We have examined the 5' terminal sequences of four Rous sarcoma virus RNAs: virion RNA and three species of intracellular mRNA which direct the synthesis of the RSV gene products. The lengths of the leaders on the RNAs were determined by the extent that they could protect cloned Rous sarcoma virus DNA fragments from S1 nuclease digestion after RNA-DNA hybridization. We found that the subgenomic mRNA's that direct the synthesis of the env and src gene products have uninterrupted spliced leader sequences of approximately 390 nucleotides, whereas virion RNA and full-length intracellular viral RNA have 5' termini homologous to the cloned viral DNA probe over at least the first 735 bases. In the accompanying manuscript we have determined the nucleotide sequence of the 5' end of the Rous sarcoma virus genome, including the candidate splice donor site identified here (Swanstrom et al., J. Virol. 41:535-541, 1982).
Structural relationship between a normal chicken DNA locus and the transforming gene of the avian acute leukemia virus MC29
Authors: Robins T , Bister K , Garon C , Papas T , Duesberg P
Published: January 2020

We screened a recombinant chicken DNA/lambda phage library for sequences homologous to the transformation-specific sequences of the avian acute leukemia virus MC29 by hybridization with molecularly cloned MC29 proviral DNA. Three cellular DNA clones were found and compared with each other and with the viral genome by physical mapping with restriction endonucleases and by heteroduplex analysis. These experiments indicated that the three cellular clones overlap and represent a single cellular locus. The RNA genome of MC29 and normal cell DNA share a homologous region of 1.6 kilobases which is interrupted in the cellular DNA by 1.0 kilobase of sequences not present in the viral genome. Hybridization of the cloned cellular DNA to viral RNA and analysis of the protected viral RNA by fingerprinting techniques indicated that there is extensive sequence homology between the helper virus-unrelated mcv sequences of the viral RNA and the cellular DNA, with only minor base differences. The cellular mcv locus, however, lacks all helper virus-related sequences of MC29, including those of the partial viral gag gene which, together with mcv, encodes the probable transforming protein of MC29. We conclude that although the mcv locus of the normal cell does not represent a complete structural homolog to the onc gene of MC29, it is probably the precursor to the onc-specific sequence in the virus.
Limited transcription of the herpes simplex virus genome when latent in human sensory ganglia
Authors: Galloway D A , Fenoglio C M , McDougall J K
Published: January 2020

Human paravertebral ganglia were examined for the presence of specific sequences of viral RNA by in situ cytological hybridization, using as probes individual fragments of herpes simplex virus type 2 DNA. Ganglia were obtained at autopsy from 40 patients, and 14 were positive for herpes simplex virus RNA. Transcripts from the left-hand 30% of the viral genome were detected in all of the herpes simplex virus-positive cases. RNA homologous to other sequences from the L component were present less frequently, and no RNA from the S component was detected. These results argue that specific transcription of the herpes simplex virus genome occurs in latently infected human ganglion cells.
In vitro reassembly of vesicular stomatitis virus skeletons
Authors: Newcomb W W , Tobin G J , McGowan J J , Brown J C
Published: January 2020

Vesicular stomatitis virus (VSV) has been disrupted with nonionic detergent plus 0.5 M NaCl under conditions which result in solubilization of the viral glycoprotein (G), matrix protein (M), and lipids, leaving the nucleocapsid in a highly extended state. Dialysis of these suspensions to remove NaCl was found to result in reassociation of nucleocapsids with M protein. Reassociated structures were highly condensed and similar in appearance to "native" VSV skeletons produced by extraction of virions with detergent at low ionic strength. For instance, electron microscopic analysis revealed that, like "native" skeletons, "reassembled" skeletons were cylindrical in shape, with diameters in the range of 51.0 to 55.0 nm and cross-striations spaced approximately 6.0 nm apart along the length of the structure. Like native skeletons, reassembled skeletons were found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to contain the viral N and M proteins, but they lacked the glycoprotein entirely. Both native and reassembled skeletons were found to be capable of in vitro RNA-dependent RNA synthesis (transcription). In vivo skeleton assembly required the presence of M protein and nucleocapsids. No skeleton-like structures were formed by dialysis of nucleocapsids in the absence of M protein or of M protein in the absence of nucleocapsids. These results provide strong support for the view that the VSV M protein plays a functional role in condensing the viral nucleocapsid in vitro and raise the possibility that it may play a similar role in vivo.
Characterization of a polypeptide present in herpes simplex virus type 2-transformed and -infected hamster embryo cells
Authors: Suh M
Published: January 2020

Transformation of hamster embryo cells by herpes simplex virus stimulated the production of a 35-kilodalton (35K) protein that was specifically immunoprecipitated, along with other polypeptides, by rabbit hyperimmune serum. This 35K polypeptide was further analyzed by partial digestion with Staphylococcus aureus V8 protease in parallel with a 35K polypeptide from herpes simplex virus type 2-infected cells. These polypeptides had almost identical partial-proteolytic cleavage maps, indicating that they are probably the same or that they are very similar polypeptides.
Effect of the arginine analog canavanine on the synthesis of Epstein-Barr virus-induced proteins in superinfected Raji cells
Authors: Bayliss G J , Wolf H
Published: January 2020

The addition of canavanine to cultures of superinfected Raji cells in the absence of arginine prevented the appearance of early antigens as defined by immunofluorescent staining. Addition of various amounts of arginine permitted the identification of at least three groups of proteins, each responding differently to the various concentrations of arginine-canavanine.
Expression of the PRC II avian sarcoma virus genome
Authors: Adkins B , Hunter T , Beemon K
Published: January 2020

We found that the genomic RNA of the replication-defective avian sarcoma virus PRC II was 4.0 kilobases long. A Northern blot analysis of the viral RNAs present in PRC II-transformed cells showed that the PRC II genome was expressed as a single 4.0 kilobase mRNA species. In vitro translation of polyadenylic acid-containing 70S virion RNA yielded two highly related proteins of 110,000 and 105,000 daltons (P110 and P105), which were synthesized from messenger activity that sedimented as expected for the 4.0 kilobase PRC II genome (at 25 to 27S). P110 and P105 were identified as in vitro translation products of the PRC II genome by immunoprecipitation and tryptic peptide mapping and were the only PRC II-specific polypeptides detected by in vitro synthesis. In addition, we found that immune complexes prepared from PRC II 70S virion RNA in vitro translation products contained a tyrosine-specific protein kinase activity. A comparison of the in vitro- and in vivo-synthesized proteins revealed that PRC II-transformed cells also contained 110,000- and 105,000-dalton proteins, which were indistinguishable from in vitro-synthesized P110 and P105 by electrophoretic mobility and tryptic peptide analysis. Both P110 and P105 were present in producer cells and in seven individual nonproducer clones. A pulse-chase analysis showed that P105 was the primary translation product of the PRC II genome and that P110 was derived from P105 by post-translational modification. Under conditions of long-term labeling with [35S]methionine, P110 and P105 were present in a molar ratio of approximately 1:1. These results indicated that the transformation-specific product of the PRC II genome, previously referred to as a single component (P105), actually consists of two polypeptides related by post-translational modification.
Participation of subgenomic retroviral mRNAs in recombination
Authors: Wang L H , Stacey D W
Published: January 2020

Envelope glycoprotein (env) mRNA from avian retroviruses was injected into cells transformed by env-deleted Bryan Rous sarcoma virus [RSV(-)]. The genetic deficiency of RSV(-) was complemented, and infectious transforming virus was released for many days after these injections. The long-term activity of the injected env mRNA is believed to be due to reverse transcription of the injected RNA after its incorporation into virus particles. The resulting subgenomic provirus, presumed to be integrated into host DNA, is able to direct the continuous synthesis of additional env mRNA. In some of these cultures, replication-competent viruses appeared many days after injection. The analysis by RNase T1 oligonucleotide fingerprinting showed that the RNA of these virus genomes contained oligonucleotides characteristic of both RSV(-) and the env mRNA injected. In all viruses analyzed the 5' two-thirds and the 3' terminus of the genome were derived from RSV(-) and the env gene from the injected mRNA. Our results thus strongly indicate that these viruses were generated via recombination between RSV(-) and env mRNA. The demonstration of involvement of an mRNA sequence in recombination may be of importance in the divergence of retroviruses and in the mechanism of interaction between retroviruses and host nucleotide sequences.
Maturation of the envelope glycoproteins of Newcastle disease virus on cellular membranes
Authors: Schwalbe J C , Hightower L E
Published: January 2020

Based on subcellular fractionation data, the following maturation pathways were proposed for the Newcastle disease virus glycoproteins. During or shortly after synthesis in rough endoplasmic reticulum, hemagglutinin-neuraminidase (HN) and fusion (F0) glycoproteins underwent dolichol pyrophosphate-mediated glycosylation, and HN assumed a partially trypsin-resistant conformation. HN began to associate into disulfide-linked dimers in rough endoplasmic reticulum, and at least one of its oligosaccharide side chains was processed to a complex form en route to the cell surface. During migration in intracellular membranes, F0 was proteolytically cleaved to F1.2. Neither HN nor F1,2 required oligosaccharide side chains for migration to plasma membranes, and cleavage of F0 also occurred without glycosylation. Virion- and plasma membrane-associated HN contained both complex and high-mannose oligosaccharide chains on the same molecule, and F1,2 contained at least high-mannose forms. Several of the properties of HN were notable for a viral glycoprotein. The oligosaccharide side chains of HN were modified very slowly in chick cells, whereas those of the G glycoprotein of vesicular stomatitis virus were rapidly processed to a complex form. Therefore, their different rates of migration and carbohydrate processing were intrinsic properties of these glycoproteins. Consistent with its slow maturation, the HN glycopolypeptide accumulated to high levels in intracellular membranes as well as in plasma membranes. Intracellular HN contained immature oligosaccharide side chains, suggesting that it accumulated in the pre-Golgi/Golgi segment of the maturation pathway. The major site of accumulation of mature HN with neuraminidase activity was the plasma membrane.
Cloned bacteriophage phi X174 DNA sequence interferes with synthesis of the complementary strand of infecting bacteriophage phi X174
Authors: van der Avoort H G , van Arkel G A , Weisbeek P J
Published: January 2020

The insertion of a particular phi X DNA sequence in the plasmid pACYC177 strongly decreased the capacity of Escherichia coli cells containing such a plasmid to propagate bacteriophage phi X174. The smallest DNA sequence tested that showed the effect was the HindII fragment R4. This fragment does not code for a complete protein. It contains the sequence specifying the C-terminal part of the gene H protein and the N-terminal part of the gene A protein, as well as the noncoding region between these genes. Analysis of cells that contain plasmids with the "reduction sequence" showed that (i) the adsorption of the phages to the host cells is normal, (ii) in a single infection cycle much less phage is formed, (iii) only 10% of the infecting viral single-stranded DNA is converted to double-stranded replicative-form DNA, and (iv) less progeny replicative form DNA is synthesized. The reduction process is phi X174 specific, since the growth of the related G4 and St-1 phages was not affected in these cells. The effect of the recombinant plasmids on infecting phage DNA shows similarity to the process of superinfection exclusion.