bluuebunny/crossref_metadata_2025 huggingface dataset:
Production and preliminary characterization of monoclonal antibodies directed at two surface proteins of rhesus rotavirus
Authors: Greenberg H B , Valdesuso J , van Wyke K , Midthun K , Walsh M , McAuliffe V , Wyatt R G , Kalica A R , Flores J , Hoshino Y
Published: January 2020

A series of monoclonal antibodies was isolated which reacted with one of two major surface proteins of rhesus rotavirus. Thirty-six monoclonal antibodies immunoprecipitated the 82-kilodalton outer capsid protein, the product of the fourth gene, the viral hemagglutinin. These monoclonal antibodies exhibited hemagglutination inhibition activity and neutralized rhesus rotavirus to moderate or high titer. Three monoclonal antibodies immunoprecipitated the 38-kilodalton outer capsid glycoprotein, the eighth or ninth gene product. These three monoclonal antibodies neutralized rhesus rotavirus to high titer and also inhibited viral hemagglutination.
Biological consequences of neuraminidase deficiency in Newcastle disease virus
Authors: Smith G W , Hightower L E
Published: January 2020

A second-step revertant (L1) of a temperature-sensitive mutant (C1) of Newcastle disease virus agglutinated erythrocytes normally but had less than 3% of the wild-type (strain AV) levels of neuraminidase activity. Revertant L1 had seven times more virion-associated N-acetylneuraminic acid (NANA) than strain AV. NANA residues on purified virions were specifically labeled with periodate and tritiated borohydride. Analyses of radiolabeled L1 virions on sodium dodecyl sulfate-polyacrylamide gels showed that most of the virion-associated NANA was in a high-molecular-weight component with an electrophoretic mobility different from that of any known viral protein. NANA was also detected in molecules with the electrophoretic mobility of the viral glycoproteins HN and F1. Revertant L1 had a twofold lower rate constant of attachment to HeLa cells than that of the wild-type. Treatment of L1 virions with Vibrio cholerae neuraminidase removed the excess NANA and returned L1 attachment kinetics to normal. Revertant N1, which has 10-fold more neuraminidase activity than L1, penetrated host cells at the same rate as L1. L1 was impaired in elution from erythrocytes. Removal of virion-associated NANA exacerbated this defect. Despite a small disadvantage in attachment and a major defect in elution relative to strain AV, revertant L1 enjoyed a slight advantage over the wild-type during a single reproductive cycle in cultured chicken embryo cells.
Linkage of the Fv-2 gene to a newly reinserted ecotropic retrovirus in Fv-2 congenic mice
Authors: Mowat M , Bernstein A
Published: January 2020

Restriction enzyme and Southern gel analyses were used to determine the number and location of endogenous ecotropic retroviruses in the germ line of several mouse strains congenic at the Fv-2 gene locus. A new endogenous ecotropic provirus was observed in the germ line of B6.S (Fv-2ss) mice, in addition to the resident provirus found in its congenic partner C57BL/6 (Fv-2rr). This new provirus was similar in structure to the C57BL provirus. The SIM strain of mice, the donors of the Fv-2s allele in B6.S mice, does not contain ecotropic proviruses, suggesting that the new provirus in the B6.S mouse strain arose by germ-line reintegration during the construction of this strain. Mendelian segregation analysis indicated that this new provirus was linked to the Fv-2 gene locus on chromosome 9. In three other Fv-2s congenic mouse strains--B10.C (47N), B6.C (H-7b), and C57BL/6J Trfa, Bgsd--no additional ecotropic endogenous viruses were detected, suggesting that the reinsertion event that occurred during the construction of B6.S is not essential for the acquisition of the Fv-2s phenotype in the C57BL genetic background. Although numerous reports of germ-line reinsertions of ecotropic virus in high-virus mouse strains have been received, the present results provide definitive evidence that similar germ-line amplifications of endogenous ecotropic virus can occur in a low-virus mouse strain.
Vaccinia virus induces cellular mRNA degradation
Authors: Rice A P , Roberts B E
Published: January 2020

The infection of mouse L cells with vaccinia virus induced a rapid inhibition of cellular polypeptide synthesis and a diversion of protein synthesis to the exclusive production of viral polypeptides. This shutoff of cell-specific protein synthesis was achieved by a novel mechanism by which the virus induced the rapid degradation of cellular mRNAs. Concurrent with the degradation of cellular mRNA, the virus proceeds in the orderly temporal expression of its own genetic information. The effect of vaccinia virus infection upon two abundant L-cell mRNAs was assessed by using the highly conserved cDNA sequences that encode chicken beta-actin and rat alpha-tubulin. Hybridization analyses demonstrated that throughout infection there is a rapid and progressive degradation of both of these mRNAs. In fact, after 3 h of infection they are reduced to less than 50% of their concentration in uninfected L cells, and between 8 to 10 h they are almost entirely degraded. This observation explains in part the mechanism by which vaccinia virus inhibits host cell protein synthesis.
Molecular cloning of integrated Gardner-Rasheed feline sarcoma virus: genetic structure of its cell-derived sequence differs from that of other tyrosine kinase-coding onc genes
Authors: Naharro G , Tronick S R , Rasheed S , Gardner M B , Aaronson S A , Robbins K C
Published: January 2020

Gardner-Rasheed feline sarcoma virus (GR-FeSV) is an acute transforming retrovirus which encodes a gag-onc polyprotein possessing an associated tyrosine kinase activity. The integrated form of this virus, isolated in the Charon 21A strain of bacteriophage lambda, demonstrated an ability to transform NIH/3T3 cells at high efficiency upon transfection. Foci induced by GR-FeSV DNA contained rescuable sarcoma virus and expressed GR-P70, the major GR-FeSV translational product. The localization of long-terminal repeats within the DNA clone made it possible to establish the length of the GR-FeSV provirus as 4.6 kilobase pairs. The analysis of heteroduplexes formed between lambda feline leukemia virus (FeLV) and lambda GR-FeSV DNAs revealed the presence of a 1,700-base-pair FeLV unrelated segment, designated v-fgr, within the GR-FeSV genome. The size of this region was sufficient to encode a protein of approximately 68,000 daltons and was localized immediately downstream of the FeLV gag gene coding sequences present in GR-FeSV. Thus, it is likely that this 1.7-kilobase-pair stretch encodes the onc moiety of GR-P70. Utilizing probes representing v-fgr, we detected homologous sequences in the DNAs of diverse vertebrate species, implying that v-fgr originated from a well-conserved cellular gene. The number of cellular DNA fragments hybridized by v-fgr-derived probes indicated either that proto-fgr is distributed over a very large region of cellular DNA or represents a family of related genes. By molecular hybridization, v-fgr was not directly related to the onc genes of other known retroviruses having associated tyrosine kinase activity.
Murine retroviral restriction genes Fv-4 and Akvr-1 are alleles of a single locus
Authors: O'Brien S J , Berman E J , Estes J D , Gardner M B
Published: January 2020

The two murine retroviral restriction genes, Fv-4 and Akvr-1, are very similar in their effects, distributions, ranges of action, and phenotypes. Akvr-1 has been shown to segregate independently in backcrosses with a variety of retroviral restriction loci, including Fv-1, Fv-2, Ril-1, and Ril-2. An allelism test cross of FRG (Fv-4R) X LCRR (Akvr-1R) hybrids mated to AKR mice failed to produce any viremic offspring. These results suggested that Akvr-1R and Fv-4R are alleles of a single locus, Fv-4, on mouse chromosome 12.
Antiviral activity released from Aedes albopictus cells persistently infected with Semliki forest virus
Authors: Newton S E , Dalgarno L
Published: January 2020

Aedes albopictus (mosquito) cells persistently infected with Semliki Forest virus released an agent which inhibited virus production by A. albopictus cells infected with homologous virus. Inhibition of virus production was accompanied by a marked reduction in the synthesis of viral RNA and viral proteins. Expression of the antiviral effect was prevented by pretreatment of cells with actinomycin. No analogous antiviral activity was detected in culture fluids of A. albopictus cells persistently infected with a flavivirus (Kunjin virus) or a bunyavirus (Bunyamwera virus).
The bacteriophage P4 alpha gene is the structural gene for bacteriophage P4-induced RNA polymerase
Authors: Barrett K J , Blinkova A , Arnold G
Published: January 2020

Two temperature-sensitive mutants of satellite phage P4 which do not synthesize P4 DNA at the nonpermissive temperature have been isolated. One of these phage is mutated in the P4 alpha gene. It complements a P4 delta mutant, but not a P4 alpha amber mutant; both mutants are phenotypically identical to alpha amber mutants in all properties studied. They synthesize P4 early proteins 1 and 2 as well as two additional P4-induced early proteins, 5 and 6, which are described here. P4 late proteins are not synthesized by these mutants and cannot be transactivated by helper phage P2. The mutants are unable to transactivate P2 late proteins from a P2 AB mutant. The P4 RNA polymerase activity which has been suggested to be involved in P4 DNA synthesis is not detected at the nonpermissive temperature. The P4 polymerase activity in partially purified extracts prepared from cells infected with the mutant at the permissive temperature is temperature sensitive. Reduced activity is found in vitro when these extracts are preincubated at 41 degrees C or assayed at temperatures higher than 37 degrees C. Thus, the P4 RNA polymerase is the product of the alpha gene. Temperature shift experiments show that the alpha gene product is required until late in the P4 cycle.
In vitro DNA synthesis by an alpha-like DNA polymerase bound to replicating simian virus 40 chromosomes
Authors: Waqar M A , Evans M J , Burke J F , Tsubota Y , Plummer M J , Huberman J A
Published: January 2020

Simian virus 40 chromosomes carry out replicative DNA synthesis in vitro which is sensitive to aphidicolin and to N-ethylmaleimide, resistant to 2',3'-dideoxythymidine-5'-triphosphate, and proportional to the amount of chromosome-associated alpha-like polymerase. Thus, an alpha-like DNA polymerase (alpha polymerase or delta polymerase) is responsible for in vitro DNA synthesis.
Synthesis and processing of glycoprotein D of herpes simplex virus types 1 and 2 in an in vitro system
Authors: Matthews J T , Cohen G H , Eisenberg R J
Published: January 2020

We carried out studies of in vitro translation and processing of glycoprotein D (gD) of herpes simplex virus types 1 and 2 by using mRNA from cells infected for 6 h and a reticulocyte lysate translation system. Polypeptides of 49,000 daltons were immunoprecipitated with anti-gD-1 sera. Each in vitro-synthesized molecule had the same methionine tryptic peptide profile as the respective in vivo precursors, pgD-1 and pgD-2. In addition, the polypeptides synthesized in vitro were larger than the corresponding molecules synthesized in the presence of tunicamycin. This suggested that each of the gD polypeptides synthesized in vitro contained a transient N-terminal signal sequence. When the translation mixture was supplemented with pancreatic microsomes, each of the gD polypeptides was converted cotranslationally to a larger-molecular-weight form. Processing involved addition of three N-asparagine-linked oligosaccharides and removal of the signal peptide. When trypsin was added after in vitro processing, a polypeptide which was 3,000 daltons smaller than the in vitro-modified form of gD was immunoprecipitated. Experiments with endo-beta-N-acetylglucosaminidase H showed that this polypeptide still contained the three N-asparagine-linked oligosaccharides. Two monoclonal antibodies, 57S (group V) and 17O (group VII), were used to further orient gD in microsomes. The group V determinant was located in the trypsin-sensitive 3,000-dalton fragment, and the group VII determinant was located in the portion of gD which was protected from trypsin. We concluded that gD is oriented with the three glycosylation sites inside the vesicles and that 3,000 daltons containing the group V determinant are located outside. Immunofluorescence studies indicated that the group V determinant of gD is inside the plasma membrane of herpes simplex virus-infected cells and that the group VII determinant is outside. This cellular orientation is consistent with predictions based on the in vitro experiments.
In vitro recombination of bacteriophage T7 DNA detected by a direct physical assay
Authors: Lee D , Sadowski P D
Published: January 2020

We developed a simple, direct, physical assay to detect genetic recombination of bacteriophage T7 DNA in vitro. In this assay two mature T7 DNA molecules, each having a unique restriction enzyme site, are incubated in the presence of a cell-free extract from T7-infected Escherichia coli cells. After extraction of the DNA, restriction enzyme digestion, and agarose gel electrophoresis, genetic recombination is detected by the appearance of a novel recombinant DNA band. Recombination frequencies as high as 13% have been observed. We used this assay to determine the genetic requirements for in vitro recombination. In agreement with results obtained previously with a biological assay, T7 recombination in vitro appears to proceed via two distinct pathways.
O antigen-dependent mutant of bacteriophage T5
Authors: Heller K J , Bryniok D
Published: January 2020

A T5 mutant is described which showed normal infection of Escherichia coli F but virtually no infection of cells lacking the E. coli F O antigen. This was due to very poor adsorption to the O antigen-deficient cells. Inactivation kinetics with anti-T5 serum and adsorption and desorption kinetics to receptor-deficient E. coli F cells suggested that the mutation did not affect the L-shaped tail fibers which mediate binding to the O antigen. Proof was obtained from genetic data; the structural gene for the L-shaped tail fibers mapped at a different position on the T5 chromosome than did the mutated gene. Since binding of the T5 mutant to the FhuA receptor protein was strongly inhibited by ferrichrome and since the mutation could not be crossed into phage BF23, we conclude that the mutation affects the receptor binding protein of the T5 tail.
Vaccinia virus RNA polymerase associated with nuclei of infected HeLa cells
Authors: Wing D , Weissbach A
Published: January 2020

Though vaccinia virus DNA and RNA replication take place predominantly in the cytoplasm of an infected cell, virus formation requires the presence of a functional nucleus in a yet undefined manner. When the nuclei from cells infected for 3 h are isolated and purified, they are found to synthesize five times more RNA in vitro than do corresponding nuclei from noninfected cells. Fifty percent of the RNA synthesized in vitro by nuclei from infected cells is vaccinia specific, and this vaccinia RNA synthesis is resistant to alpha-amanitin concentrations up to 100 micrograms/ml. Furthermore, when the RNA polymerase activities of these nuclei are separated on DEAE-Sephadex columns, 56% of the total nuclear enzyme activity is found to be the vaccinia-specific RNA polymerase known to be alpha-amanitin resistant. The nucleus associated vaccinia RNA polymerase represents 18% of the total cellular vaccinia RNA polymerase. This synthesis of vaccinia RNA in the nucleus may explain the nuclear requirement for vaccinia virus maturation.
Reversal of simian virus 40 small-t-antigen-induced theophylline resistance
Authors: Rundell K , Calenoff M , Renz C
Published: January 2020

Simian virus 40 small-t antigen allows the growth of CV-1 cells in concentrations of theophylline that normally prevent cell cycling. This effect is completely overcome by two ionophores that uncouple mitochondria and by the anti-mitochondrial drug methylglyoxal bis-(guanylhydrazone).
Nucleotide sequence of the influenza virus A/USSR/90/77 hemagglutinin gene
Authors: Concannon P , Cummings I W , Salser W A
Published: January 2020

The complete nucleotide sequence of the hemagglutinin gene of influenza virus A/USSR/90/77 was determined. Comparison of hemagglutinin amino acid sequences from H1 field strains revealed five potential antigenic sites. Four of these sites correspond to those observed for H3 hemagglutinins, whereas the fifth apparently derives from differences in the glycosylation patterns between subtypes.
Isolation and characterization of measles virus intracellular nucleocapsid RNA
Authors: Udem S A , Cook K A
Published: January 2020

Protocols have been established for the preparation of large amounts of pure measles virus intracellular nucleocapsids. As a result, it has been possible to routinely achieve nucleocapsid RNA yields of approximately 200 micrograms (from approximately 5 X 10(8) infected cells). Electrophoretic analysis of this RNA under denaturing conditions revealed a single species whose mass was estimated at approximately 4.8 X 10(6) daltons. Electron microscopic assessment of nucleocapsid RNA contour lengths corroborated the electrophoretic size determination. Total nucleocapsid RNA was shown to contain both negative- and positive-stranded species distributed in a ratio of 2 to 3 genome polarity molecules for each antigenome RNA. Hybridization studies established that all of the virus-specified polyadenylated RNAs were encoded by the negative-stranded nucleocapsid RNA and, therefore, that this nucleocapsid RNA was the measles genome. Examination of the measles virus-specified, polyadenylated transcription products by HCHO-agarose gel electrophoresis revealed at least nine distinct RNA species (rather than the six predicted measles mRNAs). The significance of these observations is discussed.
Virally coded noncapsid protein associated with bovine parvovirus infection
Authors: Lederman M , Patton J T , Stout E R , Bates R C
Published: January 2020

A phosphorylated protein (NP-1) with an Mr of 28,000 has been detected in nuclei of bovine parvovirus (BPV)-infected cells in association with chromatin. No protein in this size range was detected after infection of appropriate cells with several autonomous rodent parvoviruses although the BPV-specific protein is similar in size to noncapsid proteins associated with rabbit parvovirus or adeno-associated virus infection. Structural homology between NP-1 and a BPV capsid protein could be detected by electrophoretic analysis of the products of proteolysis with chymotrypsin. This protein can be detected after in vitro translation of RNA from BPV-infected cells and BPV-specific RNA. Homology between the in vivo- and in vitro-synthesized species was shown by the similarity of the chymotryptic products.
Arrangement of late RNAs transcribed from a 7.1-kilobase EcoRI vaccinia virus DNA fragment
Authors: Mahr A , Roberts B E
Published: January 2020

Three late transcripts have been mapped to the vaccinia virus 7.1-kilobase (kb) EcoRI F fragment, which is located approximately 85 kb from the left end of the viral genome. Hybrid selection and translation of RNA have demonstrated that these mRNAs encode three polypeptides with apparent molecular weights of 32,000 (32K), 26K, and 19K. The transcripts encoding the 32K and 19K polypeptides are synthesized in a leftward direction and overlap each other as well as the RNA encoding the early 110K polypeptide. In addition, the RNA encoding the 32K polypeptide also overlaps an early transcript of 1.35 kb (see accompanying paper). The transcript encoding the 26K polypeptide overlaps the early 2.45-, 0.6- to 0.7-, and 1.7-kb RNAs, and all four mRNAs are transcribed from left to right. The protein coding sequences for the 26K and 32K polypeptides lie outside the 7.1-kb DNA fragment. Due to their heterogeneity in size, each of the three late transcripts is undetectable as a distinct size by filter hybridization. In addition, although S1 mapping has detected the 5' terminus of the late RNA which maps entirely within this fragment, it has been unable to size and locate the 3' ends of all three transcripts, and this result indicates that the heterodisperse size of the RNAs is due to heterogeneity at the 3' ends of these transcripts. The cause of this heterogeneity in termination of transcription is not known.
Identification of a tenth mRNA of respiratory syncytial virus and assignment of polypeptides to the 10 viral genes
Authors: Collins P L , Huang Y T , Wertz G W
Published: January 2020

Nine mRNAs, their cDNA clones, and a genome transcriptional map have been reported previously for respiratory syncytial virus (P. L. Collins and G. W. Wertz, Proc. Natl. Acad. Sci. U.S.A. 80:3208-3212, 1983). We report here the identification of a 10th viral mRNA, designated mRNA 2b (molecular weight [MW] ca. 0.39 X 10(6)), that was detected by RNA (Northern) blot hybridization with cDNA clones. Analysis of a polycistronic readthrough transcript was used to deduce the position in the viral transcriptional map of the gene encoding the newly identified mRNA. The polypeptide coding assignments of 9 of the 10 respiratory syncytial virus mRNAs were determined. Individual viral mRNAs were purified by hybridization selection with nine unique, nonoverlapping cDNA clones and analyzed by translation in vitro. Each of the nine mRNAs encoded a single polypeptide chain. The coding assignments were as follows: RNA 1a (MW ca. 0.24 X 10(6)), a 9,500-dalton (9.5K) protein; RNA 1b (MW 0.26 X 10(6)), an 11K protein; RNA 1c (MW 0.26 X 10(6)), a 14K protein; RNA 2a (MW 0.38 X 10(6)), the 34K phosphorylated (P) protein; RNA 2b (MW 0.39 X 10(6)), a 36K protein; RNA 3a (MW 0.40 X 10(6)), the 26K matrix (M) protein; RNA 3b (MW 0.40 X 10(6)), a 24K protein; RNA 4 (MW 0.47 X 10(6)), the 42K major nucleocapsid (N) protein; and RNA 5 (MW 0.74 X 10(6)), a 59K protein. The cDNA clones used for the hybridization selections were respiratory syncytial virus specific and did not hybridize with uninfected-cell mRNA; therefore the proteins synthesized with the selected mRNAs were virus specific. The 9.5K, 11K, 14K, 24K, M, P, 36K, N, and 59K proteins were encoded by different mRNAs; therefore these nine proteins are all unique. The 9.5K, 11K, 14K, 24K, M, P, and N proteins synthesized in vitro with hybrid-selected mRNAs each had counterparts with the same electrophoretic mobilities in extracts of virus-infected cells. The in vitro polypeptides and their authentic counterparts were shown to be closely related by limited digest peptide mapping. The 36K and 59K polypeptides lacked counterparts with the same electrophoretic mobilities in infected cells and therefore are candidates for the unprocessed precursors of the viral F and G glycoproteins. The 10th viral mRNA, the 2,500K RNA 7, was not tested directly but is the only known mRNA of the appropriate size to encode the 200K large (L) protein of the viral nucleocapsid. These assignments account for all 10 of the reported viral mRNAs and bring to 10 the number of known unique viral proteins.
Involvement of DNA polymerase alpha in host cell reactivation of UV-irradiated herpes simplex virus
Authors: Nishiyama Y , Yoshida S , Maeno K
Published: January 2020

Aphidicolin is a potent inhibitor of both host cell DNA polymerase alpha and herpes simplex virus (HSV)-induced DNA polymerase but has no effect on DNA polymerases beta and gamma of host cells. By using an aphidicolin-resistant mutant (Aphr) of HSV, a possible involvement of DNA polymerase alpha in host cell reactivation of UV-damaged HSV was studied. Plaque formation by UV-irradiated Aphr was markedly inhibited by 1 microgram of aphidicolin per ml, which did not affect the plating efficiency of nonirradiated Aphr. Aphidicolin added before 12 h postinfection inhibited plaque formation by irradiated Aphr, which became aphidicolin insensitive after 36 h postinfection. The results strongly suggest that host cell DNA polymerase alpha is involved in the repair of UV-irradiated HSV DNA.
DNA Analysis of Insect Iridescent Virus 6: Evidence for Circular Permutation and Terminal Redundancy
Authors: Delius H. , Darai G. , Flügel R. M.
Published: January 2020

DNA analysis of small insect iridovirus 6 was performed. Combined exonuclease-restriction endonuclease digestions revealed that all resulting fragments were degraded without preference for any one DNA fragment. Upon denaturation and reannealing of native linear Chilo iridescent virus DNA (158 × 10
6
daltons), duplex DNA circles of a smaller size (140 × 10
6
daltons) with protruding tails were formed.
Combined action of mouse alpha and beta interferons in influenza virus-infected macrophages carrying the resistance gene Mx
Authors: Meyer T , Horisberger M A
Published: January 2020

In mice, the combined action of alpha and beta interferons (IFNs) against influenza viruses is modulated by the host gene Mx. High concentrations of IFN fail to prevent efficiently the replication of influenza A virus in cultured macrophages lacking the gene Mx, whereas cultured macrophages carrying Mx develop strong antiviral activity even at low concentrations of IFN. Several steps in the replication cycle of influenza virus were compared in Mx/Mx and +/+ mouse macrophages treated with IFN-alpha + beta. Uncoating was not affected. A twofold reduction in the accumulation of primary transcripts was observed in IFN-treated macrophages at the highest concentration of IFN regardless of the genetic constitution of the host cell. No evidence was obtained for inhibition of influenza virus translation in macrophages which lacked Mx when treated with IFN-alpha + beta. In contrast, a marked shut-off of influenza virus polypeptide synthesis occurred in Mx-bearing macrophages treated with these IFNs, although the primary transcripts were active in directing the synthesis of viral polypeptides in a cell-free system. We concluded that a specific inhibitory mechanism for influenza virus translation was induced by IFN-alpha + beta in macrophages bearing the resistance gene Mx.
A post-alpha gene function turns off the capacity of a host protein to bind DNA in cells infected with herpes simplex virus 1
Authors: Arsenakis M , Roizman B
Published: January 2020

HEp-2 cell proteins electrophoretically separated in denaturing polyacrylamide gels and electrically transferred to nitrocellulose sheets contain a polypeptide which efficiently binds linear native DNA end labeled with 32P but not denatured DNA. The polypeptide has an apparent molecular weight of ca. 130,000. The activity of the protein was stable, and no appreciable turnover was observed after exposure of uninfected cells to inhibitory concentrations of cycloheximide for intervals of up to 24 h. However, the activity was absent from lysates of cells harvested 6 h or later postinfection with wild-type viruses. To identify the viral function involved in the loss of DNA-binding activity, we tested the lysates of cells infected with several mutants. Thus, the DNA-binding activity was unaffected in cells infected with a temperature-sensitive mutant (herpes simplex virus 1 tsLB2) in the alpha 4 gene and was maintained at a nonpermissive temperature (39 degrees C). Experiments involving (i) temperature shift-down of cells infected with tsLB2 in the presence of cycloheximide, (ii) withdrawal of cycloheximide in the presence and absence of actinomycin D from cells infected with wild-type virus, (iii) infection of cells at 33 and 39 degrees C with herpes simplex virus 1 tsHA1 carrying a temperature-sensitive lesion in the beta 8 gene, and (iv) infection of cells in the presence of inhibitory concentrations of phosphonoacetate led to the conclusion that the viral functions responsible for the loss of DNA-binding capacity were specified by either beta or gamma genes not dependent on viral DNA synthesis for their expression.
Brain tumors of owl monkeys inoculated with JC virus contain the JC virus genome
Authors: Miller N R , McKeever P E , London W , Padgett B L , Walker D L , Wallen W C
Published: January 2020

The DNA from astrocytomas that developed in adult owl monkeys 16 to 36 months after intracranial inoculation with JC virus (JCV) was examined for the presence of the JCV genome by hybridization to cloned JCV DNA. The JCV genome was found to be integrated into the cellular DNA in all tumors examined. There was no JCV DNA in normal, uninvolved brain tissue from the same animals. Integration of the genome occurred at a limited number of sites in the cellular DNAs, indicating a clonal origin for the tumors, but none of the tumors had integration sites in common. In all but one of the tumors, there was tandem, head-to-tail integration of two or more copies of the JC genome. In a tumor which had only one integration site and could be analyzed more extensively, there appeared to be a complete copy of the JCV genome present, although deletions of small portions of the genome would not have been detected.
Isolation of the prohead core of bacteriophage T4 after cross-linking and determination of protein composition
Authors: Traub F , Keller B , Kuhn A , Maeder M
Published: January 2020

The naked core of bacteriophage T4 was isolated ex vivo after cross-linking with either glutaraldehyde or dithiobis(succinimidyl propionate). The isolated particles appeared to be morphologically identical to the cores found in thin sections, to those demonstrated in in situ lysis preparations, and to core structures assembled in vitro. Treatment with glutaraldehyde provided core particles which were morphologically well preserved, whereas dithiobis(succinimidyl propionate)-induced cross-linking was reversible and allowed analysis of the protein composition of the isolated particles. The identity of the reversibly cross-linked particles with those obtained after irreversible cross-linking was suggested by their morphology and their similar sedimentation behavior. Immunolabeling confirmed the structural presence of the main core protein in both structures. Gel electrophoresis of reversibly cross-linked cores revealed the essential head proteins gp22, gp67, and gp21, the three internal proteins IPI, IPII, and IPIII, and a 17K protein.
Characterization of the major mRNAs transcribed from the genes for glycoprotein B and DNA-binding protein ICP8 of herpes simplex virus type 1
Authors: Rafield L F , Knipe D M
Published: January 2020

The structural genes encoding the herpes simplex virus type 1 glycoprotein B and the major DNA-binding protein ICP8 have been mapped previously within the EcoRI-F restriction fragment (map coordinates 0.314 to 0.420) of the viral genome. In this study the mRNAs transcribed from these DNA sequences were identified by hybridization selection of 32P-labeled RNA and by Northern blot analysis of polyadenylated cytoplasmic RNA. A 3.4-kilobase RNA was the major mRNA homologous to the DNA sequences between coordinates 0.343 and 0.386 in which mutations in the glycoprotein B gene have been mapped. A 4.5-kilobase RNA was the major mRNA homologous to the viral DNA sequences between coordinates 0.361 and 0.417 in which mutations in the ICP8 gene have been mapped. Hybridization-selected mRNAs were translated in vitro to determine the primary translation products encoded in each region. The glycoprotein B- and ICP8-specific polypeptides were identified by immunoprecipitation with specific antisera. The translation products encoded by the glycoprotein B gene were 103,000 and 99,000 in molecular weight. The translation products encoded by the ICP8 gene were 125,000 and 122,000 in molecular weight.
Virus-Specific Antigens in Hamster Cells Transformed by Rous Sarcoma Virus
Authors: Fleissner Erwin
Published: January 2020

Virus-specific antigens were studied in hamster cells transformed by Rous sarcoma virus (RSV). Antigens were localized in the cytoplasm, as demonstrated by fluorescent antibody staining of fixed cells as well as by complement fixation (CF) following subcellular fractionation. Cytoplasmic extracts were analyzed by velocity and isopycnic centrifugation. CF antigens were found in a soluble form and in association with membranes and polyribosomes. Isolated plasma membranes had no CF antigen. Both soluble and particulate fractions with CF activity contained the same antigenic determinants by Ouchterlony analysis. These antigenic determinants were identical to those released by ether treatment of RSV.
Streptomycin-Induced Phenotypic Suppression of Hydroxylamine-Induced Nonsense Mutants in the rII A Cistron of Bacteriophage T4
Authors: Schwartz Robert D. , Bryson Vernon
Published: January 2020

Twenty-one hydroxylamine-induced rII A cistron nonsense mutants were tested for streptomycin (SM)-induced phenotypic suppression by exposing
Escherichia coli
SBO (nonpermissive host) to phage in the presence and absence of SM. All nine amber, four of six ochre, and five of six opal mutants were phenotypically suppressible by SM. For suppressible mutants, the ratio of the average burst size in the presence of SM to size in the absence of SM ranged from 12 to 242 for the ambers, 3 to 33 for the ochres, and 4 to 14 for the opals. Increased susceptibility of the amber mutants to SM-induced phenotypic suppression relative to the susceptibility of the opal and ochre mutants may reflect a neighboring base effect, such that a 3′-terminal adenine inhibits misreading of a 5′-terminal uracil.
Protection of Vaccinia from Heat Inactivation by Nucleotide Triphosphates
Authors: Munyon William , Mann Judith , Grace James T.
Published: January 2020

The presence of adenosine triphosphate, guanosine triphosphate, cytosine triphosphate, or uridine triphosphate reduced the rate of inactivation of vaccinia when heated at 50 C. The virus-associated nucleoside triphosphate phosphohydrolases (adenosine triphosphatase, guanosine triphosphatase, cytosine triphosphatase, and uridine triphosphatase) and ribonucleic acid polymerase were also protected from heat inactivation by these compounds. These obervations are best explained by postulating that ribonucleoside triphosphates bind to enzymes in the virus particle, and that these enzyme-substrate complexes are more resistant to thermal denaturation than are the enzymes without their substrates. The kinetics of heat inactivation of the vaccinia ATP phosphohydrolase activity is biphasic, suggesting that there are two proteins in the vaccinia particle that have this enzyme activity but they have different kinetics of heat inactivation. Any of the vaccinia-associated nucleotide phosphohydrolase activities are protected from heat inactivation by the presence of any one of the respective nucleoside triphosphates. This observation suggests that there is a single enzymatic site in vaccinia that is able to react with any ribonucleoside triphosphate.
Acid-Soluble Material of Adenovirus
Authors: Boulanger P. A. , Jaume F. , Flamencourt P. , Biserte G.
Published: January 2020

Two methods are described for adenovirus capsid disruption and extraction of acid-soluble proteins from the viral core. The acid-soluble material of adenovirus consisted of three major proteins, one of them being selectively extracted after mild disruption of the virus particle. Some chemical properties of these proteins are reported.
Protein-Synthetic Activity of Ribosomes from Interferon-Treated Cells
Authors: Kerr Ian M. , Sonnabend J. A. , Martin E. M.
Published: January 2020

Cell-free protein-synthetic systems from normal and interferon-treated chick cells were compared. No difference was found in the amino acid incorporation activities of such ribosome-cell sap systems or in their response to polyuridylic acid. Throughout a variety of experiments we failed to detect the formation of a discrete peak of virus-specific polysomes, when ribosome monomers and subunits (from interferon-treated or control cells) were incubated with labeled Sindbis or Semliki Forest virus ribonucleic acid (RNA). Some binding of viral RNA did occur, but the complexes formed were evident in sucrose gradients as a broad, rapidly sedimenting shoulder on the ribosome monomer peak. Interferon pretreatment of cells did not affect the formation of these complexes in vitro, nor did it alter their rate of breakdown on incubation under amino acid incorporation conditions. Experiments with inhibitors of protein synthesis showed that such “breakdown” was not dependent upon amino acid incorporation and was not an index of translation. In these respects, our results are in marked contrast to those of Marcus and Salb. These results, together with our failure to detect any significant change in the protein composition of ribosomes from interferon-treated cells, suggest that such treatment does not result in a modification of the ribosome per se. They do not, however, rule out the involvement of a factor(s) required for ribosomes and viral RNA to function in viral protein synthesis. Indeed, it remains likely that interferon acts through such a mechanism, although the precise level at which the inhibition occurs remains to be elucidated.
Electron Microscopy of the Nucleic Acid of Mouse Mammary Tumor Virus
Authors: Sarkar Nurul H. , Moore Dan H.
Published: January 2020

Mouse mammary tumor virus (MTV) was isolated from the milk of RIII mice by density-gradient centrifugation in Ficoll. The homogeneity of the preparation was demonstrated in electron micrographs. The nucleic acid was extracted with phenol in the presence of Pronase. Its viral origin was attested by failure of ribo-nuclease and deoxyribonuclease treatment of the virus preparation to destroy the filamentous molecules; after phenol extraction, the molecules were destroyed by ribonuclease but not by deoxyribonuclease. Rotary shadowed preparations were examined in the electron microscope. The length distribution of the RNA filaments showed peaks at 1.2, 2.4, and 3.6 μm. The molecular weight of the longest molecule of MTV-RNA was estimated as 3.6 × 10
6
daltons.
Preparation of Infectious Cell-Free Herpes-Type Virus Associated with Marek's Disease
Authors: Cook M. Katherine , Sears Johnna F.
Published: January 2020

Cell-free transmission of the herpes-type virus of Marek's disease was obtained by demineralized water treatment of infected chick embryo fibroblasts.
Purified Rabbit Interferon: Attempts to Demonstrate Interferon-Specific
3
H-Protein
Authors: Yamazaki Shudo , Wagner Robert R.
Published: January 2020

3
H-protein present in highly purified preparations of rabbit interferon was not conclusively separated from noninterferon, cellular
14
C-proteins by co-chromatography on carboxymethyl-Sephadex or by co-electrophoresis on acid or neutral polyacrylamide gels.
Spectrum of Physical Properties Among the Virions of a Whole Population of Vaccinia Virus Particles
Authors: Sharp D. G. , McGuire Peter M.
Published: January 2020

Populations of virions released from cultures of L cells infected with vaccinia virus are composed of particles which differ substantially from each other in sedimentation rate and buoyant density. Clumps of two and three virions sediment enough faster than single particles so that fractions containing only singles and others with predominantly pairs can be isolated. The observed velocity range for single particles is much greater than that attributable to diffusion and convection in the centrifuge. Plaquing efficiency is three times higher in a small fraction of the slowest-moving virions than in the major part of the population, even though no size difference can be seen in the electron microscope. Isopycnic densities in potassium tartrate range from 1.15 to 1.23, enough to account for the observed range in velocities. Centrifugation was done in the BXIV zonal rotor at very low virion concentration (less than 10
8
per ml at any point in the spectrum). Virus count and state of aggregation were determined by electron microscopy.
Serological Relationship of the Tacaribe Complex of Viruses to Lymphocytic Choriomeningitis Virus
Authors: Rowe Wallace P. , Pugh Wendell E. , Webb Patricia A. , Peters Clarence J.
Published: January 2020

By means of the indirect fluorescent-antibody test, cross serological reactivity was demonstrated between lymphocytic choriomeningitis (LCM) virus and the viruses of the Tacaribe complex. Antisera to all members of the Tacaribe complex reacted with LCM virus; LCM antisera gave significant staining of Amapari virus, but minimal or inconsistent reactions with Tacaribe virus, and no reaction with two other viruses of the Tacaribe complex. A low level cross-reaction was observed in complement fixation tests of Machupo and Pichinde antisera against LCM antigen. Immunization with Tacaribe and Amapari viruses did not protect mice against challenge with LCM virus. Because of the identical appearance of the virions, the sharing of antigens, and the many biological similarities between LCM and the Tacaribe complex viruses, it is proposed that they be considered as constituting a new taxonomic group of viruses.
Isolation of Two Plaque Variants from the Adenovirus Type 2-Simian Virus 40 Hybrid Population Which Differ in Their Efficiency in Yielding Simian Virus 40
Authors: Lewis Andrew M. , Rowe Wallace P.
Published: January 2020

Studies on the adenovirus type 2-simian virus 40 (SV40) hybrid population demonstrated two genetically stable variants within this population, which were isolated by plaquing in African green monkey kidney cells. These variants were similar in that each induced SV40 T antigen in human embryonic kidney cells and contained similar concentrations of nonhybrid adenovirus type 2 virions and adenovirus-encapsidated particles containing the infectious SV40 genome. These variants differed markedly, however, in their ability to produce SV40 viral antigen in human embryonic kidney cells and the efficiency with which they produce SV40 plaques in monkey cell monolayers. It is postulated that the differences in SV40-yielding efficiency between these variants lie in the nature of the recombinant deoxyribonucleic acid composing the genome of the hybrid particles.
Mechanism of Oncogenic Transformation by Rous Sarcoma Virus
Authors: Balduzzi Piero , Morgan Herbert R.
Published: January 2020

Chick embryo fibroblasts brought into stationary phase of growth by maintenance in serum-free Eagle's MEM medium were infected with the Bryan strain of Rous sarcoma virus (B-RSV) and incubated for 18 hr in the presence of 5-bromo-deoxyuridine (BUdR). The cells were then allowed to resume growth and deoxyribonucleic acid (DNA) synthesis by addition of an enriched F12 medium containing serum and RSV antibody to prevent spread of viral infection. After 48 hr, the cultures were exposed for various periods to visible light, overlaid with solid culture medium, and observed for the appearance of foci of transformed cells. In cultures treated with BUdR at the time of infection, exposure to light resulted in a suppression of focus formation of from 50 to 90% in various experiments. Treatment with BUdR for 18 hr before infection or on the day after infection, followed by exposure to light, had no effect on focus formation. In cultures in which almost all cells were infected, treatment with BUdR followed by exposure to light did not result in cell death. This suggests that suppression of transformation is not due to selective killing of infected cells by this treatment but rather to the intracellular inactivation of the transforming ability of Rous sarcoma proviral DNA.
Quantitative Characteristics of the Transformation of Hamster Cells by PARA (Defective Simian Virus 40)-Adenovirus 7
Authors: Duff Ronald , Rapp Fred
Published: January 2020

An in vitro method for the quantitative measurement of transformation in hamster embryo fibroblasts by the PARA [defective simian virus 40 (SV40)]-adenovirus 7 hybrid has been developed. Transformation by PARA particles followed one-hit kinetics with a ratio of 1 focus-forming unit per 250 plaque-forming units. The method of viral adsorption had a direct effect upon the total number of foci which developed but not on the quantitative aspects of this assay. A fluorescent-focus assay was developed which provided a direct correlation of the observed morphological transformation and the presence of the PARA genome. This fluorescent-focus assay utilized detection of the SV40 tumor antigen, which was present in all foci transformed by PARA. Single foci induced by PARA were isolated and grown into cell lines. Two types of foci were observed and isolated; the first contained cells having a cuboidal or SV40-type morphology, and the second consisted of epithelial or adenovirus-type transformed cells. Both types contained the SV40 tumor and SV40 surface antigens as determined by the indirect fluorescence technique; however, only the epithelial cells contained the adenovirus 7 tumor antigen. All five cell lines which were injected into weanling Syrian hamsters were found to be oncogenic. These cell lines induced antibodies to both SV40 and adenovirus 7 tumor antigens in tumor-bearing animals.
Suppression of Adsorption Properties of a z Mutant of Bacteriophage T4 by r Mutations
Authors: Rutberg Blanka
Published: January 2020

The products of bacteriophage T4 r genes influence the organization of the phage-adsorption apparatus in a noncatalytic way.
Human-Mouse Hybrid Cell Lines and Susceptibility to Poliovirus
Authors: Wang Richard , Pollack Robert , Kusano Toshihisa , Green Howard
Published: January 2020

A number of human-mouse somatic hybrid cell lines have been prepared, containing from 3 to 12 human biarmed chromosomes. These lines were susceptible to poliovirus type 1, producing viral yields comparable to those of the human parental cells. A small proportion of the cells of these lines survived the polio infection, and their progeny were solidly resistant to reinfection with the virus. Both sensitive and resistant hybrids produced virus following infection with viral ribonucleic acid, indicating that the cytoplasm of the resistant hybrids was able to support viral multiplication. Viral adsorption studies carried out at 4 C showed that the resistant sublines had negligible ability to adsorb the virus. It was concluded that the hybrid cells became resistant to polio through loss of the human chromosome bearing the gene for the receptor substance.
Human-Mouse Hybrid Cell Lines and Susceptibility to Polio Virus
Authors: Kusano T. , Wang R. , Pollack R. , Green H.
Published: January 2020

A number of human-mouse hybrid cell lines with partial human chromosome complements were sensitive to poliovirus because the cells contained the viral receptor substance of human origin. Infection of the lines with one type of poliovirus regularly led to the survival of a few cells, whose progeny were found to be resistant to all types of poliovirus. Comparison of the chromosomes of sensitive hybrids and their resistant sublines showed no consistent difference in the number of biarmed human chromosomes of any group. The number of acrocentrics was always lower in the resistant hybrids than in the corresponding sensitive lines. It is suggested that the human chromosome bearing the polio receptor gene is an acrocentric.