bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Degradation of Newly Synthesized Nonmessenger Simian Virus 40 Transcripts
Authors: Chiu Nancy H. , Radonovich Michael F. , Thoren Marilyn M. , Salzman Norman P.
Published: January 2020

By pretreating simian virus 40-infected BSC-1 cells with glucosamine, [
3
H]uridine labeling of both cellular and viral RNA can be halted instantaneously by addition of cold uridine. We have studied the fate of pulse-labeled viral RNA from cells at 45 h postinfection under these conditions. During a 5-min period of labeling, both the messenger and nonmessenger regions of the late strand were transcribed. After various chase periods, nuclear viral species which sediment at 19, 17.5, and 16S were observed. Nuclear viral RNA decays in a multiphasic manner. Of the material present at the beginning of the chase period, 50% was degraded rapidly with a half-life of 8 min (initial processing). This rapidly degraded material was that fraction of the late strand which did not give rise to stable late mRNA species. Forty percent was transported to the cytoplasm, and 10% remained in the nucleus as material which sedimented in the 2 to 4S region. These 2 to 4S viral RNAs had a half-life of 3 h, and hybridization studies suggest that they are in part coded for by the late-strand nonmessenger region and are derived from the initial nuclear processing step. Another part is coded for by the late-strand messenger region and may be generated by some subsequent nuclear cleavages of 19S RNA into 17.5 and 16S RNAs. Transport of nuclear viral RNA into the cytoplasm was detected after a 5-min pulse and a 7-min chase. The maximum amount of labeled viral RNA was accumulated in the cytoplasm after a 30-min to 1-h chase. At least two viral cytoplasmic species were observed. Kinetic data suggest that 19S RNA is transported directly from the nucleus. Whether cytoplasmic 16S is formed by cleavage of 19S RNA in the cytoplasm is not clear. The half-lives of cytoplasmic 19 and 16S RNAs can be approximated as 2 and 5 h, respectively.
No homology between double-stranded RNA and nuclear DNA of yeast
Authors: Hastie N D , Brennan V , Bruenn J A
Published: January 2020

We investigated the possibility of sequence of homology between yeast DNA and one of the double-stranded RNAs present in many strains of Saccharomyces cerevisiae. These double-stranded RNAs are encapsidated in virus-like particles, which appear to be similar to the viruses of higher fungi. Contrary to a recent report (M. Vodkin, J. Virol. 21:516--521, 1976), we find no such homology.
Characterization of Rauscher murine leukemia virus envelope glycoprotein receptor in membranes from murine fibroblasts
Authors: Kalyanaraman V S , Sarngadharan M G , Gallo R C
Published: January 2020

Plasma membrane preparations from KA31 (mouse) cells contained receptors for the binding of Rauscher murine leukemia virus (R-MuLV) envelope glycoprotein, gp70. This binding was demonstrated by gel filtration of a mixture of the microsomal fraction of the cells and 125I-labeled gp70. A rapid and convenient assay was developed to measure the complex formation between the membrane receptors and gp70 involving specific precipitation of the complex by 3 to 4% polyethylene glycol. The complex formation was responsive to the concentrations of both the receptor and gp70 and also to changes in temperature and pH. The gp70 binding was a noncooperative, saturable process, and an association constant of 3.5 X 10(8) M-1 was estimated from the binding data. The complex formation was reversible and a near-total exchange of 125I-labeled gp70 in the complex was achieved by incubation with excess of unlabeled gp70. The complex formation was inhibited by protein denaturing agents, guanidine-hydrochloride and urea. Pretreatment of the membrane fractions with either chymotrypsin or phospholipase C led to a loss of the membrane-associated receptor activity, indicating that a lipoprotein structure was important for the receptor function, consistent with the observation that nonionic detergents strongly inhibited the complex formation.
Effect of spermidine on bacteriophage P22 infection
Authors: Dasgupta B , Chakravorty M
Published: January 2020

The effect of spermidine on phage P22 infection of Salmonella typhimurium has been found to depend on the time of addition of spermidine with respect to the time of addition of the phage and also on the composition of the growth medium. If spermidine was added prior to or within a short time after infection, the cells survived. Under this condition the invading DNA appeared to remain trapped in the cell membrane, and there was no expression of the phage genome. If spermidine was added after the initiation of the infective process, the replication of the phage was inhibited but the cells did not survive. If spermidine was added after DNA synthesis was over, there was no effect of spermidine on phage multiplication. Spermidine was found to affect phage DNA synthesis but not host DNA synthesis.
Transcription pattern of in vivo-labeled late simian virus 40 RNA: equimolar transcription beyond the mRNA 3' terminus
Authors: Ford J P , Hsu M T
Published: January 2020

We have examined the pattern of RNA transcription on the L (late) DNA strand late in the simian virus 40 virus infectious cycle by separating pulse-labeled RNA chains according to size and hybridizing to an ordered series of DNA fragments obtained by restriction enzyme digestion. From this analysis, the 5' end of the nascent transcript occurs a short distance counterclockwise from 0.735. Transcription proceeds in a clockwise direction. There is equimolar transcription for at least 1,000 nucleotides beyond the 3' end of the mRNA (0.175). The 3' terminus for the largest molecules is in 0.43--0.655. Molecules which represent more than one circuit of the genome are not more than 1% of the total population of nascent molecules. Implications of these findings for models of the biogenesis of mRNA are discussed.
Analysis of unintegrated avian RNA tumor virus double-stranded DNA intermediates
Authors: Hsu T W , Sabran J L , Mark G E , Guntaka R V , Taylor J M
Published: January 2020

Previous studies by Guntaka et al. have shown that the unintegrated DNA intermediates of avian RNA tumor virus replication can be readily isolated from cultures of the quail tumor line QT-6 at 1 day after infection. The intermediates include double-stranded linear and covalently closed circular DNA species. Using the analysis procedure of Southern together with previously obtained information regarding the sites of action of certain restriction endonucleases on avian sarcoma virus DNA, we have further characterized the viral DNA intermediates. Evidence is presented that, relative to the RNA genome, most of the linear species possess a direct terminal sequence redundancy equivalent to 0.5 X 10(6) +/- 0.3 X 10(6) daltons of double-stranded DNA. Some of the circular forms also possess a sequence redundancy of 0.21 X 10(6) +/- 0.03 X 10(6) daltons.
Envelope proteins and replication of vesicular stomatitis virus: in vivo effects of RNA+ temperature-sensitive mutations on viral RNA synthesis
Authors: Martinet C , Combard A , Printz-Ané C , Printz P
Published: January 2020

Temperature-sensitive (ts) mutants of vesicular stomatitis virus belonging to complementation groups III and V were investigated for their in vivo RNA synthesis. The sucrose gradient patterns of the RNA species which they produced at nonpermissive temperature (39.2 degrees C) were systematically compared under different experimental conditions: variation of input multiplicity and of time of infection, superinfection with T particles, and temperature shifts. Finally, a more precise analysis of the various RNA species synthesized was carried out. It appeared that the characteristics of RNA synthesis specified at 39.2 degrees C by tsIII or tsV mutants differed from the normal RNA synthesis of vesicular stomatitis virus wild type. Their common depression at 39.2 degrees C in virion-like RNA (38S) production--i.e., so-called genome replication--was tentatively paralleled with the concomitant ts events which have been previously shown to affect the two viral envelope proteins. An overproduction of the RNA transcripts was described for mutants in group III and posed the question of a regulation process to determine the amount of RNA to be transcribed.
Restriction insensitivity in bacteriophage T5. II. Lack of EcoRI modification in T5+ and T5ris mutants
Authors: Davison J , Brunel F
Published: January 2020

Neither bacteriophage T5+ nor its EcoRI-sensitive ris mutants became modified during growth on an EcoRI-modifying host. For this reason, the rare ris plaques able to grow on the EcoRI-modifying host were always due to revertant phage rather than to modified ris mutants. The ris mutations resulted in the creation of new EcoRI cleavage sites in the terminally repetitious first-step transfer DNA, and analysis of T5 ris revertants showed loss of these sites and restoration of the wild-type restriction pattern. Natural EcoRI sites present in the second-step transfer DNA were never lost in T5ris revertants, indicating that these are irrelevant to in vivo restriction and are protected during growth on the restricting host.
Analysis of integrated avian RNA tumor virus DNA in transformed chicken, duck and quail fibroblasts
Authors: Sabran J L , Hsu T W , Yeater C , Kaji A , Mason W S , Taylor J M
Published: January 2020

The state of integration of avian sarcoma virus DNA in the genomes of transformed chicken, duck, and quail fibroblasts was deduced by means of restriction enzyme digestion of total cell DNA, gel electrophoresis, and subsequent analysis by the procedure of Southern. The cells used in these studies were either mass-infected cultures or clones of infected cells selected by their ability to form colonies in agar. For both mass-infected cultures and clones of cells of all three species, we found that integration occurred at a specific site on the viral genome but appeared to occur at many sites on the cell genome. At least some of the integrated viral DNA existed as intact nonpermuted species flanked by direct terminal repeats of at least 0.134 megadalton (217 base pairs). For each of 12 transformed quail clones studied, it was possible to detect, after digestion with Kpn I, unique junctions between viral and cellular DNA. That is, at our level of analysis, the integration site on the cell genome for each clone was different. However, within each of the 17 chicken and 9 duck clones of transformed cells, a heterogeneity presumably occurred during the outgrowth of the cell clone population, in that we could not readily detect identifiable cell-virus junction fragments.
Gene D5 product of bacteriophage T5: DNA-binding protein affecting DNA replication and late gene expression
Authors: McCorquodale D J , Gossling J , Benzinger R , Chesney R , Lawhorne L , Moyer R W
Published: January 2020

Gene D5 is not only necessary for replication of bacteriophage T5 DNA and for shutoff of expression of some early genes, but has been found to be necessary also for the expression of late T5 genes. The polypeptide product of gene D5 has been identified, an intragenic map of gene D5 has been constructed, and the direction of transcription of gene D5 has been established. The polypeptide coded by gene D5 has been shown to be a DNA-binding protein with affinity for both double- and single-stranded DNA.
Restricted replication of two alphaviruses in ricin-resistant mouse L cells with altered glycosyltransferase activities
Authors: Gottlieb C , Kornfeld S , Schlesinger S
Published: January 2020

Two mouse L cell variant lines (CL 3 and CL 6) selected for resistance to the toxic plant lectin ricin were restricted in their ability to replicate the two alphaviruses Sindbis virus and Semliki Forest virus. CL 3 cells have been shown to exhibit increased CMP-sialic acid:glycoprotein sialyltransferase and GM3 synthetase activities, whereas CL 6 cells have been shown to contain decreased UDPgalactose:glycoprotein galactosyltransferase and UDP-N-acetylglucosamine:glycoprotein N-acetylglucosaminyltransferase activities. The adsorption of Sindbis virus to CL 6 cells was considerably reduced, suggesting that the loss or inaccessibility of the receptors for Sindbis virus accounted for a major defect in virus production in these cells. In contrast, CL 3 synthesized Sindbis viral RNA and proteins but were unable to convert the precursor glycoprotein PE2 to the structural protein E2. The cleavage of PE2 to E2 was also blocked in both CL 3 and CL 6 cells infected with Semliki Forest virus.
Poliovirus Polyuridylic Acid Polymerase and RNA Replicase Have the Same Viral Polypeptide
Authors: Flanegan James B. , Baltimore David
Published: January 2020

A poliovirus-specific polyuridylic acid [poly(U)] polymerase that copies a polyadenylic acid template complexed to an oligouridylic acid primer was isolated from the membrane fraction of infected HeLa cells and was found to sediment at 4 to 5S on a linear 5 to 20% glycerol gradient. When the poly(U) polymerase was isolated from cells labeled with [
35
S]methionine and was analyzed by glycerol gradient centrifugation and polyacrylamide gel electrophoresis, the position of only one viral protein was found to correlate with the location of enzyme activity. This protein had an apparent molecular weight of 62,500 based on its electrophoretic mobility relative to that of several molecular weight standards and was designated p63. When the poly(U) polymerase was isolated from the soluble fraction of a cytoplasmic extract, the activity was found to sediment at about 7S. In this case, however, both p63 and NCVP2 (77,000-dalton precursor of p63) cosedimented with the 7S activity peak. When the 7S polymerase activity was purified by phosphocellulose chromatography, both p63 and NCVP2 were found to co-chromatograph with poly(U) polymerase activity. The poliovirus replicase complexed with its endogenous RNA template was isolated from infected cells labeled with [
35
S]methionine and was centrifuged through a linear 15 to 30% glycerol gradient. The major viral polypeptide component in a 26S peak of replicase activity was p63, but small amounts of other poliovirus proteins were also present. When the replicase-template complex was treated with RNase T1 before centrifugation, a single peak of activity was found that sedimented at 20S and contained only labeled p63. Thus, p63 was found to be the only viral polypeptide in the replicase bound to its endogenous RNA template, and appears to be active as a poly(U) polymerase either as a monomer protein or as a 7S complex.
Characterization of mycoplasmavirus MVL2 DNA
Authors: Lombardi P S , Cole B C
Published: January 2020

The size and molecular configuration of mycoplasmavirus MVL2 DNA are presented. The DNA was shown to be a covalently closed circular duplex molecule with a molecular weight of 7.4 X 10(6). In sucrose gradients at neutral pH, the form I and form II DNA molecules have sedimentation values of approximately 29S and 23S, respectively. Under alkaline conditions, the form I and form II have S values of 70 and 20, respectively.
Inhibition of coronavirus 229E replication by actinomycin D
Authors: Kennedy D A , Johnson-Lussenburg C M
Published: January 2020

The yields of human coronavirus 229E grown in L132 cells were markedly inhibited by actinomycin D, the 50% inhibitory dose being 0.1 micron/ml. Inhibition was maximal during the early phase of virus replication, did not appear to involve viral RNA synthesis per se, and was shown to be dependent on the input multiplicity of infection.
Novel antiviral activity found in the media of Sindbis virus-persistently infected mosquito (Aedes albopictus) cell cultures
Authors: Riedel B , Brown D T
Published: January 2020

Aedes albopictus (mosquito) cells persistently infected with Sindbis virus for a period of 6 months release into the medium a low-molecular-weight material capable of specifically reducing the yields of Sindbis virus during the "acute phase" of infection in mosquito cells. The antiviral activity was produced in detectable levels at 3 days after infection, and its concentration in the extracellular medium increased thereafter. The antiviral activity was inactivated by treatment with the enzyme protease K and heat. It was not activated by treatment with antibody prepared against extracts of Sindbis virus-infected BHK-21 cells. The antiviral activity differs from interferon produced by vertebrate cells in that it is virus specific as well as cell specific.
“sarc” Sequence Transcription in Moloney Sarcoma Virus-Transformed Nonproducer Cell Lines
Authors: Bondurant Maurice , Ramabhadran Rajani , Green Maurice , Wold William S. M.
Published: January 2020

3
H-labeled complementary DNA(sarc), complementary to the murine sarcoma virus (MSV)-specific portion of the Moloney MSV (M-MSV) genome, was prepared. M-MSV-specific RNA was then quantitated in the cytoplasm of several M-MSV-transformed, non-virus-producing, clonal NIH 3T3 cell lines. These lines, designated 71 N clones 5, 6, and 3, have been characterized previously by the degree to which they exhibit transformation properties and transcribe Moloney murine leukemia virus-related RNA (S. Salzberg and M. Green, J. Virol.
13
:1001-1004, 1974; N. Tsuchida and M. Green, J. Virol.
14
:587-591, 1974). By the criteria of cell morphology and agglutination by concanavalin A, cells of clone 5 are highly transformed, cells of clone 6 are almost normal in the sense that they resemble the parent NIH 3T3 cells, and cells of clone 3 are phenotypically intermediate. In the present study, the amounts of cytoplasmic MSV-specific RNA correlated well with the relative degrees of transformation of the cell lines, varying over 35-fold between the least transformed (clone 6) and most transformed (clone 5) lines. Superinfection of either clone 5 or clone 6 with Moloney murine leukemia virus resulted in a fivefold increase in the MSV-specific RNA in the cell cytoplasm. Evidence from
3
H-labeled complementary DNA:cell DNA hybridization studies indicated that the quantity of M-MSV-specific RNA in the nonproducer lines was not directly related to DNA provirus copy number in the cell DNA. Although clones 5 and 6 differ greatly in transformation characteristics and in MSV-specific RNA content, they each apparently contain about two copies of MSV-specific DNA sequence per haploid genome. Thus, factors such as site of provirus integration may be of primary importance in determining virus-specific transcription and cell transformation.
Involvement of DNA gyrase in replication and transcription of bacteriophage T7 DNA
Authors: De Wyngaert M , Hinkle D C
Published: January 2020

Growth of bacteriophage T7 is inhibited by the antibiotic coumermycin A1, an inhibitor of the Escherichia coli DNA gyrase. Since growth of the phage is insensitive to the antibiotic in strains containing a coumermycin-resistant DNA gyrase, this enzyme appears to be required for phage growth. We have investigated the effect of coumermycin on the kinetics of DNA, RNA, and protein synthesis during T7 infection. DNA synthesis is completely inhibited by the antibiotic. In addition, coumermycin significantly inhibits transcription of late but not early genes. Thus, E. coli DNA gyrase may play an important role in transcription as well as in replication of T7 DNA.
In vitro, the major ribosome binding site on Rous sarcoma virus RNA does not contain the nucleotide sequence coding for the N-terminal amino acids of the gag gene product
Authors: Darlix J L , Spahr P F , Bromley P A , Jaton J C
Published: January 2020

Ribosomes from the reticulocyte lysate bind strongly and mainly to a region located in the 5' end of the Rous sarcoma virus RNA molecule between residues 9 and 53. This binding involves the participation of initiator tRNA and is sensitive to inhibitors of initiation of protein synthesis such as 7-methyl-GMP and aurintricarboxylic acid. The nucleotide sequence of this ribosome binding site has been determined: it conatains a GUG codon centered at position 26 that is not in phase with any termination codon within the 5' end nucleotide sequence of the RNA that we have analyzed (101 residues). However, the predicted N-terminal amino acid sequence starting from this GUG codon (or even from any AUG or GUG codon in the 5' end of the RNA) does not coincide with that of the in vitro-synthesized product of the 5' end proximal gag gene. Nevertheless, inhibition of ribosome binding to this site is accompanied by an inhibition of the in vitro translation of the gag gene.
Intracellular forms of simian virus 40 nucleoprotein complexes. I. Methods of isolation and characterization in CV-1 cells
Authors: Fernandez-Munoz R , Coca-Prados M , Hsu M T
Published: January 2020

A new method was developed for isolation of intracellular forms of simian virus 40 (SV40) nucleoprotein complexes from SV40-infected CV-1 cells late in the infectious cycle. In contrast to the Triton extraction method, which yields only a 60-70S complex, this new procedure yielded three forms of SV40 nucleoprotein complexes: complex I, complex II, and the nature virion (V). The three nucleoprotein complexes differed in physical as well as biochemical properties. Complex I, which is only a small portion of the total SV42 nucleoprotein complexes late during infection, was active in synthesizing both SV40-specific DNA and RNA. Pulse-labeling experiments suggest the following metabolic pathway: I leads to II leads to V. Conversion of complex I to II occurred shortly after the completion of SV40 DNA replication and resulted in the inactivation of the biosynthetic activities of I.
Vaccinia Virus Replication I. Requirement for the Host-Cell Nucleus
Authors: Hruby Dennis E. , Guarino Linda A. , Kates Joseph R.
Published: January 2020

Using cytochalasin B-induced enucleation techniques, we examined the ability of vaccinia virus to replicate in the absence of the host-cell nucleus in several mammalian cell lines. It was found that virus-infected enucleated cells (cytoplasts) prepared from BSC-40, CVC, and L cells were incapable of producing infectious progeny virus. The nature of this apparent nuclear involvement was studied in detail in BSC-40 cells. Modulations designed to maximize cytoplast integrity and longevity, such as reduction of the growth temperature and initial multiplicity of infection, did not improve virus growth in cytoplasts. Sodium dodecyl sulfate-polyacrylamide gel analysis of the [
35
S]methionine pulse-labeled proteins synthesized in vaccinia virus-infected cytoplasts demonstrated that both early and late viral gene products were being expressed at high levels and with the proper temporal sequence. Vaccinia virus cytoplasmic DNA synthesis, as measured by [
3
H]thymidine incorporation, peaked at 3 h postinfection and was 70 to 90% of control levels in cytoplasts. However, in the cytoplasts this DNA was not converted to a DNase-resistant form late in infection, which was consistent with the failure to isolate physical particles from infected cytoplasts. Treatment of vaccinia virus-infected cells with 100 μg of rifampin/ml from 0 to 8 h to increase the pools of viral precursors, followed by subsequent removal of the drug, resulted in a threefold increase virus yield. This treatment had no effect on virus-infected cytoplasts. Finally, vaccinia virus morphogenesis was studied under an electron microscope in thin sections of virus-infected cells and cytoplasts which had been prepared at various times during a single-step growth cycle. It was apparent that, although early virus morphogenetic forms appeared, there was no subsequent DNA condensation or particle maturation in the cytoplasts. These results suggest that vaccinia virus requires some factor or function from the host-cell nucleus in order to mature properly and produce infectious progeny virus.
Interruption-deficient mutants of bacteriophage T5 I. Isolation and general properties
Authors: Rogers S G , Godwin E A , Shinosky E S , Rhoades M
Published: January 2020

Mutations of bacteriophage T5 were isolated which lack one or more of the natural single-chain interruptions that occur in the mature DNA of this virus. Interruption-deficient mutants were detected by screening survivors of hydroxylamine mutagenesis for altered DNA structure by electrophoresis in agarose slab gels. Over 60 independent mutants were isolated from a survey of approximately 800 phages particles. All of the mutants were viable and could be grouped into two classes. Mutants in one class lacked one of the localized sites where interruptions occur in T5 DNA. To date, mutants that affect five different sites have been obtained. Mutants in the other class were essentially free from interruptions or had a reduced frequency of interruptions throughout the genome. The members of this class included several amber mutants. Complementation tests indicated that at least two genes are required for the presence of interruptions in mature T5 DNA.
Transformation of human embryonic kidney cells by human papovarirus BK
Authors: Purchio A F , Fareed G C
Published: January 2020

Infection of secondary human embryonic kidney (HEK) cells with human papovavirus BK (BKV) resulted in cellular lysis and degeneration within 7 days. After 30 days, multilayered colonies of transformed cells were found and subcultured for analyses. These BK-HEK cells uniformly expressed the BKV T-antigen but were only 1% V-antigen positive. They produced infectious virus and were resistant to superinfection by BKV. They reached a saturation density of 1.3 x 10(5) cells per cm2 in medium with 5% fetal calf serum, were able to grow in medium containing 2% serum, and did not form colonies in soft agar or tumors in nude mice. Nonintegrated, superhelical BKV DNA was detected in the noncloned cells as expected because they were persistently infected and contained RNA transcripts complementary to both early and late regions of the BKV genome. Analysis of T-antigen-positive clonal isolates of these BK-HEK cells by the Southern technique revealed an absence of free viral DNA and the presencce of integrated BKV DNA sequences corresponding to the early region of the BKV genome. These studies demonstrate the stable transformation of human cells by BKV. However, the transformed human cells which retain and express part of the BKV genome do not fully manifest the growth properties of other papovarirus-transformed cells.
Nucleotide sequence analysis of two simian virus 40 mutants with deletions in the late region of the genome
Authors: Contreras R , Cole C , Berg P , Fiers W
Published: January 2020

Two mutants of simian virus 40, dl-1261 and dl-1262, have deletions that map between coordinated 0.90 and 0.95 (Cole et al., J. Virol 24:277--294, 1977). Both affect the structure of the two minor proteins VP2 and VP3. The precise location and size of the deletions have now been determined by nucleotide sequence analysis. Mutant dl-1261 is deleted of 54 base pairs, is temperature sensitive for the protein defined by the D complementation group, and promotes the synthesis of shorter VP2 and VP3 polypeptides. Mutant dl-1262 is viable irrespective of temperature and has a deletion of 36 base pairs, 23 of which overlap the deletion in dl-1261. Since these mutants produce normal VP1, the deleted regions probably have no function in the splicing of precursor RNA to the VP1 mRNA.
Anatomy of herpes simplex virus DNA. XI. Apparent clustering of functions effecting rapid inhibition of host DNA and protein synthesis
Authors: Fenwick M , Morse L S , Roizman B
Published: January 2020

Herpes simplex virus type 2 (HSV-2) strains inhibit the synthesis of both DNA and protein of the host cell more rapidly than HSV-1 strains. Several intertypic HSV-1 X HSV-2 recombinants and parental strains were examined for their ability to inhibit rapidly the synthesis of host protein and DNA. The two functions cosegregated in all of eight recombinants tested and are therefore controlled by the same gene or by different genes in the same region of the viral DNA.
Physical Map of the DNA Genome of
Autographa californica
Nuclear Polyhedrosis Virus
Authors: Miller Lois K. , Dawes Katherine P.
Published: January 2020

A physical map of the 88 × 10
6
dalton, circular DNA genome of
Autographa californica
nuclear polyhedrosis virus was constructed. The complete order of
Bam
HI and
Xma
I restriction enzyme sites was determined. The
Eco
RI and
Hin
dIII fragments were partially ordered, and their general locations, relative to the
Bam
HI and
Xma
I maps, were determined. Alterations in the restriction endonuclease fragment patterns of natural genotypic variants of
A. californica
nuclear polyhedrosis virus, including
Trichoplusia ni
MEV nuclear polyhedrosis virus, were located on the physical map. Alterations were found throughout the
A. californica
nuclear polyhedrosis virus DNA genome.
Unstable resistance of G mouse fibroblasts to ecotropic murine leukemia virus infection
Authors: Yoshikura H , Naito Y , Moriwaki K
Published: January 2020

G mouse cells were resistant to N- and NB-tropic Friend leukemia viruses and to B-tropic WN 1802B. Though the cells were resistant to focus formation by the Moloney isolate of murine sarcoma virus, they were relatively sensitive to helper component murine leukemia virus. To amphotropic murine leukemia virus and to focus formation by amphotropic murine sarcoma virus, G mouse cells were fully permissive. When the cell lines were established starting from the individual embryos, most cell lines were not resistant to the murine leukemia viruses. Only one resistant line was established. Cloning of this cell line indicated that the resistant cells constantly segregated sensitive cells during the culture; i.e., the G mouse cell cultures were probably always mixtures of sensitive and resistant cells. Among the sensitive cell clones, some were devoid of Fv-1 restriction. Such dually permissive cells, and also feral mouse-derived SC-1 cells, retained glucose-6-phosphate dehydrogenase-1 and apparently normal number 4 chromosomes. The loss of Fv-1 restriction in these mouse cells was not brought about by any gross structural changes in the vicinity of Fv-1 on number 4 chromosomes.
Unusual Baculovirus of the Parasitoid Wasp
Apanteles melanoscelus
: Isolation and Preliminary Characterization
Authors: Krell Peter J. , Stoltz Donald B.
Published: January 2020

A baculovirus present in the female reproductive tract of the parasitoid wasp
Apanteles melanoscelus
has been isolated and partially characterized. Viral DNA is double stranded, circular, and of highly variable molecular weight ranging from 2 × 10
6
to 25 × 10
6
; the DNA is of homogeneous density at ρ = 1.694 g/ml. Acrylamide gels resolve 18 polypeptide bands in the case of purified virions; four to five of these appear in a semipurified nucleocapsid preparation. The electrophoretic profiles obtained are compared with those of two other baculoviruses.
Origin of small RNA in von Magnus particles of influenza virus
Authors: Nakajima K , Ueda M , Sugiura A
Published: January 2020

A clone of recombinant virus obtained from the cross between WSN and Hong Kong strains of influenza virus gave rise to progeny containing predominantly von Magnus particles. In the electropherogram of virus RNA, the P3 gene was markedly diminished, and a new species of RNA (extra RNA) was present in addition to eight gene segments. The origin of the extra RNA was studied by two-dimensional gel electrophoresis of T1 RNase-generated oligonucleotides. Four out of five large oligonucleotide spots present in the extra RNA matched to those contained by the P3 gene. It was concluded that the extra RNA was derived from the P3 gene probably by deletion. The possible origin of the spot which was present in the extra RNA but not in eight gene segments including P3 was discussed.
Bacteriophage T4 alt gene maps between genes 30 and 54
Authors: Goff C G
Published: January 2020

Two- and three-factor crosses proved that the T4 alt gene, which codes for a virion-associated NAD+:protein ADP-ribosyltransferase, is located between genes 30 and 54.
Synthesis of Long Complementary DNA in the Endogenous Reaction by Equine Infectious Anemia Virus
Authors: Rice Nancy R. , Coggins Leroy
Published: January 2020

In the endogenous reverse transcriptase reaction, equine infectious anemia virus is able to synthesize complementary DNA (cDNA) of 8,000 nucleotides in high yield. After 2 h in 50 μM dNTP, about 2.8 μg of cDNA per mg of protein is produced, almost 30% of which is long cDNA. The system thus compares favorably with the other two well-characterized endogenous reaction systems, Moloney murine leukemia virus and avian sarcoma virus. Elongation rates of 100 to 150 nucleotides per min have been observed; these rates are comparable to those seen with purified avian myeloblastosis virus reverse transcriptase and significantly higher than those observed in vivo. In the absence of actinomycin D, equine infectious anemia virus does not require high dNTP levels for either optimal incorporation or long cDNA synthesis. The amount of long cDNA synthesized is maximal at 2 h in 50 μM dNTP; neither longer time nor higher dNTP levels (through 1.8 mM) increased this yield. Half-maximum yield in 2 h was achieved at about 15 μM dNTP, which is very similar to the published

K
M

's for isolated avian and murine reverse transcriptases. Total incorporation, on the other hand, continues to rise slowly through 1 mM dNTP; the half-maximum was 30 to 50 μM dNTP. In the presence of 100 μg of actinomycin D per ml, however, higher dNTP levels are required for long cDNA synthesis. We conclude that equine infectious anemia virus is exceptionally well-suited to studies of the physical organization of the retrovirus genome and to investigations of the mechanism of synthesis of the double-standard cDNA endogenous reaction product.
Immunochemical Characterization of Plaque Mutants of Simian Virus 40
Authors: Ozer H. L. , Takemoto K. K. , Kirschstein R. L. , Axelrod D.
Published: January 2020

Analysis of large and small plaque mutants of simian virus 40 using antisera prepared against each has revealed quantitative and possibly qualitative antigenic differences for each plaque type. A sensitive micro radioisotope precipitation test permitted evaluation of immunochemical similarities and differences of capsid antigens by inhibition of precipitation.
Formation of Viral Ribonucleic Acid and Virus in Cells that are Permissive or Nonpermissive for Murine Encephalomyelitis Virus (GDVII)
Authors: Sturman Lawrence S. , Tamm Igor
Published: January 2020

GDVII virus growth in BHK-21 cells, a permissive host for the virus, resembled productive infections with other picornaviruses. Virus yields ranged from 100 to 600 plaque-forming units (PFU)/cell. Virus replication in HeLa cells, a nonpermissive host for GDVII virus, was characterized by virus yields of only 0.1 to 5 PFU/cell. Similar low yields of virus have been obtained from HeLa cells at all multiplicities of input up to 6,000 per cell. The progeny particles from HeLa cells were, like the infecting particles, restricted in the HeLa cell host. Despite the great difference in final yields of virus from BHK-21 and HeLa cells, the times when maximal yields were reached were similar. GDVII virus stock grown in BHK-21 cells was designated HeLa
-
. A variant of GDVII virus which is capable of extensive growth in HeLa cells was obtained. This variant, designated HeLa
+
GDVII virus, was passaged serially in HeLa cells. Virus yields of 50 to 150 infective virus particles per cell were obtained from infection of HeLa cells with HeLa
+
GDVII virus. The major species of HeLa
+
virus-specific ribonucleic acid (RNA) produced was single stranded and sedimented with an
S
value of 35
S
. The rate of accumulation of HeLa
+
virus-specific RNA in HeLa cell cultures was about four times that of HeLa
-
RNA. The amount of virus-specific HeLa
+
RNA formed in HeLa cells was several-fold greater than that of HeLa
-
RNA. With HeLa
-
parent GDVII virus undergoing productive replication in BHK-21 cells or abortive replication in HeLa cells, the major species of virus-specific RNA produced was single stranded and sedimented with an approximate
S
value of 35
S
. The amount of HeLa
-
virus-specific RNA extracted from BHK-21 cells was several-fold greater than the amount obtained from HeLa cells.
Critical Arginine Residue for Maintaining the Bacteriophage Tail Structure
Authors: Kozloff L. M. , Lute M. , Crosby L. K. , Wong R. , Stern B.
Published: January 2020

The addition of 0.2
m l
-arginine to various T-even bacteriophage preparations inactivated the virus preparations irreversibly. The virus particles were even more sensitive to added
d
-arginine and
l
-homoarginine than to
l
-arginine but were unaffected by arginine analogues with either an altered carboxyl group or guanidyl group. Treatment of phage T2H with 2,3-butanedione, a reagent which specifically reacts with the guanidyl portion of arginine residues, resulted in the apparent in-activation of most of the virus particles. However, after incubation of the treated particles at
p
H 7.5 at 37 C for 1 hr in the absence of butanedione, the original virus titer almost completely returned. The reactivation was completely inhibited by the presence of 0.2
m d
-arginine. It appeared that the virus protein coat was sufficiently plastic so that the initial conformational change resulting from the alteration of an arginine residue (to possibly an ornithine residue) was at least partially reversible and that the virus tail proteins then refolded to produce a stable and active virus particle. These reactivated virus particles were not sensitive to inactivation by
d
-arginine but could now be rapidly inactivated by
l
-ornithine. Virus particles inactivated by arginine have altered tail structures. They have contracted tail sheaths still attached to tail plates and still contain tail cores. These properties of virus particles indicate that there is a free carboxyl group and a guanidyl group spatially equivalent to an arginine residue on one component of the virus tail which bind reversibly by means of polar linkages to another tail component. These bonds maintain the integrity of the virus tail. Added arginine appears to compete with this endogenous viral arginine for the binding sites and then to favor an irreversible conformational change.
Filamentous Structures of Type 2
Herpesvirus hominis
Infection of the Chorioallantoic Membrane
Authors: Couch Ernest F. , Nahmias André J.
Published: January 2020

In view of recent recognition of the existence of two
Herpesvirus hominis
(HVH) types with antigenic and biological differences, an electron microscopic study was undertaken of pocks produced on the choriallantoic membrane of embryonated eggs after infection with type 1 and type 2 HVH strains. Besides the typical morphological features of herpesvirus infection noted by several investigators, it was observed that type 2 HVH also produced microtubules measuring approximately 19 nm in both nucleus and cytoplasm. Although the nature of these filamentous structures is still unclear, consideration is given in this paper to the possibility that they may represent viral structural subunits, aberrant forms or neoantigens.
Functions of the Two Particles of Tobacco Rattle Virus
Authors: Sänger Heinz L.
Published: January 2020

Functions of long and short particles of five different tobacco rattle virus (TRV) systems were studied by complementation experiments with the corresponding long and short species of ribonucleic acid (RNA). The progeny of long RNA species alone was proteinless or “free” infectious long RNA, whereas short RNA species alone did not replicate by themselves but appeared to be dependent on long RNA for replication. When both types of RNA derived from the same isolate were inoculated together, particulate virus with long and short particles was produced in more than 50% of the resulting primary infections. These virus systems obtained by homologous complementation resembled the parent isolates in all their characteristics. In addition, heterologous complementation tests were performed with long and short RNA, each derived from another isolate. Heterologous interaction could be observed in only 2 out of 20 possible combinations. As a result, two “mixed” TRV systems with respect to their particle length distributions were obtained, since their long and short particles resembled the ones from the other isolate. The symptoms produced by these mixed viruses were determined by the corresponding long RNA and appeared not to be influenced by the heterologous short one. However, the protein coat of both particles of the “mixed” viruses was specified by the corresponding noninfectious short RNA. Therefore, TRV is a system of at least two functionally defective and mutually complementing components which appear to be specialized in early and late functions.
Herpeslike Virus Isolated from Spontaneously Degenerated Tissue Culture Derived from Leukemia-susceptible Guinea Pigs
Authors: Hsiung G. D. , Kaplow L. S.
Published: January 2020

A herpeslike virus was consistently isolated from leukemia-susceptible strain 2 guinea pigs, but not from other strains known to be resistant to this leukemia.
Proteins of Vasicular Stomatitis Virus
Authors: Kang C. Y. , Prevec L.
Published: January 2020

Infection of L cells with vesicular stomatitis virus results in the release, into the cell-free fluid, of four antigenic components separable by rate zonal centrifugation on sucrose gradients. The largest antigens are the infectious (B) particle and a shorter noninfectious, autointerfering (T) particle. The two small antigens are characterized by sedimentation coefficients of approximately 20
S
and 6
S
. Treatment of purified B or T particles with sodium deoxycholate results in the release from the particle of a nucleoprotein core which can be purified on sucrose gradient and which has a sedimentation coefficient characteristic of the virus from which it arose. Utilizing purified antigens labeled with
14
C-amino acids during growth, we examined the protein constituents of each antigen by acrylamide-gel electrophoresis. The proteins of B and T particles are identical, each containing one minor (virus protein 1) and three major (virus proteins 2, 3, and 4) proteins, numbered in order of increasing mobility. Virus protein 3 originates from the nucleoprotein core, whereas proteins 2 and 4 come from the coat. The origin of virus protein 1 is not known. The 20
S
antigen contains a single protein equivalent to virus protein 3, whereas the 6
S
antigen shows a single protein which is similar to, but probably distinct from, virus protein 2.
Ribonucleic Acid Synthesis in Chick Embryo Cells Infected with Fowl-Plague Virus
Authors: Skehel J. J. , Burke D. C.
Published: January 2020

Increases in ribonucleic acid (RNA) polymerase activity were detected in both the nuclear and ribosomal fractions of chick embryo cells infected with fowl-plague virus. These were observed only in the presence of all four nucleoside triphosphates and were not affected by actinomycin D. The RNA polymerase activity of the ribosomal fraction was shown to be associated with a component of infected cells of sedimentation coefficient approximately 70
S
. This component also contained infected cell-specific RNA and protein molecules.
Induction of P1 Prophage and Superinfection by Bacteriophage T1
Authors: Christensen J. R. , Werner Elizabeth R.
Published: January 2020

Induction of the resident prophage did not permit restricted phage T1 to replicate freely in P1-lysogenic hosts. A few induced cells did become infectible.
Properties of Single- and Double-stranded Ribonucleic Acid from Barley Plants Infected with Bromegrass Mosaic Virus
Authors: Hiruki Chuji
Published: January 2020

Incorporation of
32
P into nucleic acids in barley plants infected with bromegrass mosaic virus (BMV) was analyzed by chromatography on methylated albumin kieselguhr (MAK) columns. Treatment with actinomycin D reduced the synthesis of ribosomal ribonucleic acid (RNA) to low levels and allowed the detection of the three components of BMV-RNA in vivo. The kinetic study on
32
P incorporation into these BMV-RNA components suggested that a single cleavage occurred in some of the intact RNA shortly after completion of its synthesis, giving rise to the small and medium components. Chromatographic analyses also revealed a double-stranded, ribonuclease-resistant RNA which has been purified by differential extraction, sucrose-density gradient centrifugation, and MAK column chromatography. This RNA sediments at approximately 14
S
, is alkali-labile, and has a sharp thermal transition with a T
m
of 96 C in 0.1 × standard saline citrate buffer, as determined by susceptibility to ribonuclease. The RNA is absent in uninfected barley plants.
Gene with Quantitative Effect on Circulating Interferon Induced by Newcastle Disease Virus
Authors: de Maeyer Edward , de Maeyer-Guignard Jaqueline
Published: January 2020

Circulating interferon production, induced by Newcastle disease virus, is about seven times higher in C
57
Black mice than i Balb/c/Gif mice. A Mendelian analysis was carried out and circulating interferon production was measured in reciprocal F
1
hybrids, in the F
2
generation, in progeny of backcrosses of F
1
hybrids to either parent strain, and in second backcross progeny. The results indicate that a single, partly dominant, autosomal factor is responsible for the difference in circulating interferon production between both parent strains.
Mutant of φX174 Accessible to Host-controlled Modification
Authors: Schnegg Barbara , Hofschneider Peter Hans
Published: January 2020

A proflavine-induced φX174 mutant was isolated, φX174 sB1, which is accessible to restriction and modification by B-host specificity, but not by K-host specificity.
Physical and Genetic Mapping of the SPO2 Prophage on the Chromosome of
Bacillus subtilis
168
Authors: Inselburg J. W. , Eremenko-Volpe T. , Greenwald L. , Meadow W. L. , Marmur J.
Published: January 2020

It has been found by density transfer and genetic mapping experiments that prophage SPO2 is linked to the antibiotic resistance marker
ery-1
in
Bacillus subtilis
168.
qin101: Promoter mutation which allows the constitutive expression of the late genes
Authors: Dambly C , Delstanche M , Gathoye A M
Published: January 2020

We describe the isolation and characterization of a mutant (lambda qin101) which renders lambda growth Q independent. We have shown that this mutation creates a new promoter, located between genes P and Q, which results in the constitutive expression of the entire Q late region.
Functional similarity between the early antigens of simian virus 40 and human papovavirus BK
Authors: Lai C J , Goldman N D , Khoury G
Published: January 2020

The functional properties of the early antigens of simian virus 40 (SV40) and human papovavirus BK (BKV) were investigated. Infection of African green monkey kidney cells with BKV permitted the bidirectional replication of an early temperature-sensitive mutant (tsA) at a nonpermissive temperature. Conceivably, an early gene product (T-antigen) of BKV can substitute functionally for the defective SV40 T-antigen. On the other hand, SV40 DNA replication remained undetectable in human embryonic kidney cells preinfected with BKV, suggesting that BKV early antigens alone are not sufficient to provide for the replication of SV40. Preinfection of African green monkey kidney cells with BKV restored the normal pattern of late lytic SV40 transcription, suppressing the overproduction of early RNA by an SV40 tsA mutant at the nonpermissive temperature. Furthermore, preinfection of African green monkey kidney cells with BKV supported the growth of adenovirus type 2, providing a "helper function" similar to that provided by SV40 for the growth of human adenovirus in monkey kidney cells.