bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro transcription of a cloned vaccinia virus gene by a soluble extract prepared from vaccinia virus-infected HeLa cells
Authors: Foglesong P D
Published: January 2020

Faithful transcription of a vaccinia virus gene was accomplished in vitro by using a soluble extract prepared from vaccinia virus-infected HeLa cells. Specific transcription of the cloned vaccinia virus gene was detected by using template DNA restricted within the transcribed region. The vaccinia virus gene was not transcribed by extracts prepared from uninfected HeLa cells even with supplementation by purified vaccinia virus RNA polymerase, nor was a clone of adenovirus 2 DNA bearing the major late promoter transcribed by the extract from vaccinia virus-infected HeLa cells. Thus, infection by vaccinia virus altered cellular transcriptional specificity to favor expression of vaccinia virus genes. RNA synthesis by the infected cell extract was resistant to alpha-amanitin but strongly inhibited by beta, gamma-imido ATP and novobiocin.
A vaccinia virus DNase preparation which cross-links superhelical DNA
Authors: Lakritz N , Foglesong P D , Reddy M , Baum S , Hurwitz J , Bauer W R
Published: January 2020

Multiple DNA-dependent enzyme activities have been detected in highly purified preparations of a single-strand-specific nuclease from vaccinia virus. These enzyme preparations were extensively purified and characterized by using superhelical DNAs as substrates. In particular, the nuclease activity was monitored by the extent of conversion of supercoiled closed duplex DNA (DNA I) to nicked circular DNA (DNA II), which could subsequently be converted to duplex linear DNA (DNA III) by prolonged incubation with the enzyme. DNA species which were not substrates for the enzyme included relaxed closed duplex DNA, DNA II which had been prepared by nuclease S1 treatment or by photochemical nicking of DNA I, and DNA III. With plasmid pSM1 DNA as substrate, the extent of cleavage of DNA I to DNA II was found to increase with superhelix density above a threshold value of about -0.06. The linear reaction products were examined by gel electrophoresis after restriction enzyme digestion of the DNAs from plasmids pSM1 and pBR322 and of the viral DNAs from bacteriophage phi X174 (replicative form) and simian virus 40, and the map coordinate locations of the scissions were determined. These products were further examined by electron microscopy and by gel electrophoresis under denaturing conditions. Electron micrographs taken under partially denaturing conditions revealed molecules with terminal loops or hairpins such as would result from the introduction of cross-links at the cutting sites. These species exhibited snapback renaturation. The denaturing gel electrophoresis experiments revealed the appearance of new bands at locations consistent with terminal cross-linking. With pSM1 and pBR322 DNAs, this band was shown to contain DNA that was approximately twice the length of a linear single strand. The terminal regions of the cross-linked linear duplex reaction products were sensitive to nuclease S1 but insensitive to proteinase K, suggesting that the structure is a hairpin loop not maintained by a protein linker. A similar structure is found in mature vaccinia virus DNA.
Hemagglutinin-neuraminidase protein of the paramyxovirus simian virus 5: nucleotide sequence of the mRNA predicts an N-terminal membrane anchor
Authors: Hiebert S W , Paterson R G , Lamb R A
Published: January 2020

The nucleotide sequence of a cloned cDNA copy of the mRNA coding for the hemagglutinin-neuraminidase of the paramyxovirus SV5 was determined. There was a single large open reading frame on the mRNA which encoded a protein of 565 amino acids with a molecular weight of 62,134. The deduced amino acid sequence indicated that the only major hydrophobic region in the protein sufficiently long to anchor the protein in the membrane is located near the N terminus (amino acids 18 to 36). It is suggested that, like the influenza virus neuraminidase, hemagglutinin-neuraminidase of paramyxoviruses is oriented with its N terminus inserted into the membrane.
Specific properties of two enteric adenovirus 41 clones mapped within early region 1A
Authors: Allard A K , Wadell G , Evander K M , Lindman G K
Published: January 2020

Enteric adenovirus type 40 (Ad40) and Ad41 form the sixth subgenus of human adenoviruses. They are associated with infantile diarrhea but cannot be isolated in conventional cell cultures. The genome of the fastidious enteric Ad41 has been cloned, and the cleavage sites of the genome produced by restriction endonucleases BamHI, EcoRI, HpaI, NruI, PvuI, and SalI have been mapped. To develop useful hybridization methods for direct detection of adenoviruses, a restriction fragment library containing Ad41 DNA, with plasmid pBR322 as vector, has been constructed. Clones have been isolated which contain 8 of 10 possible BamHI fragments of Ad41, inserted into the BamHI cleavage site of the vector. Two of these clones are particularly useful for the detection of adenoviruses. One clone detects members of all human adenovirus subgenera, and the second clone is specific for enteric adenoviruses, in particular Ad41. A conspicuous absence of detectable homology was noted at 1.5 to 3.3 map units of the Ad41 genome in hybridizations against other serotypes of adenoviruses, including the closely related enteric Ad40. This sequence corresponds to the 5' portion of early region Ia.
Different membrane anchors allow the Semliki Forest virus spike subunit E2 to reach the cell surface
Authors: Riedel H
Published: January 2020

The Semliki Forest virus spike subunit E2, a membrane-spanning protein, was transported to the plasma membrane in BHK cells after its carboxy terminus, including the intramembranous and cytoplasmic portions, was replaced by respective fragments of either the vesicular stomatitis virus glycoprotein or the fowl plague virus hemagglutinin. The hybrid proteins were constructed by cDNA fusion. Upon a transient expression they could be localized at the cell surface by immunofluorescence with specific antibodies directed against any of the protein fragments.
Protection against rotavirus-induced gastroenteritis in a murine model by passively acquired gastrointestinal but not circulating antibodies
Authors: Offit P A , Clark H F
Published: January 2020

Newborn mice suckled on dams immunized either orally or parenterally with primate rotavirus SA-11 were protected against diarrhea induced by SA-11 virus challenge. Experimental oral administration of milk from orally immunized dams protected suckling mice against challenge; protective activity was detected both in the anti-rotavirus immunoglobulin A (IgA) and IgG fractions, but IgA was more potent in vivo than IgG. Oral administration of milk from parentally immunized dams also protected suckling mice against challenge; in this case, protective activity was detected in the anti-rotavirus IgG fraction. In newborn mice foster-nursed by seronegative dams, circulating rotavirus-specific antibodies in high titer did not protect mice against oral SA-11 virus challenge. It appears that the most effective rotavirus vaccine will be that which induces an efficient production of antibodies active at the intestinal cell surface.
Induction of angiosarcoma by a c-erbB transducing virus
Authors: Tracy S E , Woda B A , Robinson H L
Published: January 2020

Recently, 12 new transductions of c-erbB have been identified in a series of Rous-associated virus type 1-induced erythroleukemias. During the passage of these new transducing viruses it has become apparent that the erythroleukemia in chicken 5005 contained two different c-erbB transducing viruses. One induces erythroblastosis, whereas the second induces angiosarcoma. The angiosarcoma- and erythroblastosis-inducing viruses appear to have had a common ancestor, since tumors induced by each contain a novel, 4.3-kilobase c-erbB-related EcoRI fragment. The angiosarcoma-inducing virus has been named avian angiosarcoma virus and is designated for the chicken in which it originated.
Herpes simplex virus 1 reiterated S component sequences (c1) situated between the a sequence and alpha 4 gene are not essential for virus replication
Authors: Hubenthal-Voss J , Roizman B
Published: January 2020

The herpes simplex virus 1 genome consists of two components, L and S, each containing unique sequences flanked by inverted repeats. Each of the 6.5-kilobase pair inverted repeats of the S component, designated a'c' and ca, contains an approximately 700-base pair sequence (designated c1) located between the a sequence and the 3' terminus of the alpha 4 gene. Like the a sequence, c1 consists of direct repeats and unique sequences. Its function is not known. To probe for its function, we constructed a plasmid containing a viral thymidine kinase (TK) gene inserted into the c1 sequence. The construct was recombined into the genome of a TK- virus by cotransfection with intact viral DNA and selection for TK+ virus. As predicted from previous studies (Knipe et al., Proc. Natl. Acad. Sci. U.S.A. 75:3896-3900, 1978), the TK gene was found to be present in both copies of the c1 sequence in the R3104 virus. To delete the c1 sequence we constructed a plasmid containing 4 kilobase pairs of pBR322 flanked by an a sequence and by structural sequences of the alpha 4 gene. In this instance the cells were transfected with the construct and R3104 DNA; the progeny of the transfection was plated in the presence of 5-bromo-2'-deoxyuridine, and the selection was for TK- virus (R3158). The pBR322 DNA sequences replaced the c1 at both termini of the S component in R3158 DNA, but a sequence homologous to c1 was present in proximity to the 3' terminus of the alpha 4 gene. The results indicate that the c1 region has no significant role in the replication of the virus in cell culture. The advantage of inserting the pBR322 sequence is that it permits efficient cloning of large herpes simplex virus 1 DNA fragments by simple ligation of digests and transformation of appropriate Escherichia coli strains. The effortless selection of recombinants carrying inserts in both copies of the c1 restates the usefulness of this technique for selection of insertion deletion recombinants and underscores the rapid emergence of sequence identity at both ends of the reiterated regions of the S component as previously reported (Knipe et al., Proc. Natl. Acad. Sci. U.S.A. 75:3896-3900, 1978).
Isolation and structural characterization of cap-binding proteins from poliovirus-infected HeLa cells
Authors: Lee K A , Edery I , Sonenberg N
Published: January 2020

In poliovirus-infected HeLa cells, poliovirus RNA is translated at times when cellular mRNA translation is strongly inhibited. It is thought that this translational control mechanism is mediated by inactivation of a cap-binding protein complex (comprising polypeptides of 24 [24-kilodalton cap-binding protein], 50, and approximately 220 kilodaltons). This complex can restore the translation of capped mRNAs in extracts from poliovirus-infected cells. We have previously shown that the virally induced defect prevents interaction between cap recognition factors and mRNA. Here, we show that the cap-binding protein complex (and not the 24-kilodalton cap-binding protein) has activity that restores the cap-specific mRNA-protein interaction when added to initiation factors from poliovirus-infected cells. Thus, the activity that restores the cap-specific mRNA-protein interaction and that which restores the translation of capped mRNAs in extracts from poliovirus-infected cells, copurify. The results also indicate, by an alternative assay, that the cap-binding protein complex is the only factor inactivated by poliovirus. We also purified cap-binding proteins from uninfected and poliovirus-infected HeLa cells. By various criteria, the 24-kilodalton cap-binding protein is not structurally modified as a result of infection. However, the 220-kilodalton polypeptide of the cap-binding protein complex is apparently cleaved by a putative viral (or induced) protease. By in vivo labeling and m7GDP affinity chromatography, we isolated a modified cap-binding protein complex from poliovirus-infected cells, containing proteolytic cleavage fragments of the 220-kilodalton polypeptide.
Molecular cloning of proviral DNA and structural analysis of the transduced myc oncogene of avian oncovirus CMII
Authors: Walther N , Lurz R , Patschinsky T , Jansen H W , Bister K
Published: January 2020

Molecularly cloned proviral DNA of avian oncogenic retrovirus CMII was isolated by screening a genomic library of a CMII-transformed quail cell line with a myc-specific probe. On a 10.4-kilobase EcoRI fragment, the cloned DNA contained 4.4 kilobases of CMII proviral sequences extending from the 5' long terminal repeat to the EcoRI site within the partial (delta) complement of the env gene. The gene order of CMII proviral DNA is 5'-delta gag-v-myc-delta pol-delta env-3'. All three structural genes are partially deleted: the gag gene at the 3' end, the env gene at the 5' end, and the pol gene at both ends. The delta gag (0.83 kilobases)-v-myc (1.50 kilobases) sequences encode the p90gag-myc transforming protein of CMII. In comparison with the p110gag-myc protein of acute leukemia virus MC29, p90gag-myc lacks amino acids corresponding to additional 516 bases of gag sequences and 12 bases of 5' v-myc sequences present in the MC29 genome. Nucleotide sequence analysis of CMII proviral DNA at the delta gag-v-myc and the v-myc-delta pol junctions revealed significant homologies between avian retroviral structural genes and the cellular oncogene c-myc precisely at the positions corresponding to the gene junctions in CMII. Furthermore, the delta gag-v-myc junction in CMII corresponds to sequence elements in gag and C-myc that are possible splicing signals. The data suggest that transduction of cellular oncogenes may involve RNA splicing and recombination with homologous sequences on retroviral vectors. Different sequence elements of both the retroviral vectors and the c-myc gene recombined during genesis of highly oncogenic retroviruses CMII, MC29, or MH2.
Intracellular transport of herpes simplex virus gD occurs more rapidly in uninfected cells than in infected cells
Authors: Johnson D C , Smiley J R
Published: January 2020

A mouse L cell line which expresses the herpex simplex virus type 1 immediate-early polypeptides ICP4 and ICP47 was cotransfected with a cloned copy of the BglII L fragment of herpes simplex virus type 2, which includes the gene for gD, and the plasmid pSV2neo, which contains the aminoglycosyl 3'-phosphotransferase (agpt) gene conferring resistance to the antibiotic G418. A G418-resistant transformed cell line was isolated which expressed herpes simplex virus type 2 gD at higher levels than were found in infected cells. The intracellular transport and processing of gD was compared in transformed and infected cells. In the transformed Z4/6 cells gD was rapidly processed and transported to the cell surface; in contrast, the processing and cell surface appearance of gD in infected parental Z4 cells occurred at a much slower rate, and gD accumulated in nuclear membrane to a greater extent. Thus, the movement of HSV-2 gD to the cell surface in infected cells is retarded as viral glycoproteins accumulate in the nuclear envelope, probably because they interact with other viral structural components.
An avirulent G1 glycoprotein variant of La Crosse bunyavirus with defective fusion function
Authors: Gonzalez-Scarano F , Janssen R S , Najjar J A , Pobjecky N , Nathanson N
Published: January 2020

La Crosse virus, a member of the California serogroup of the family Bunyaviridae, causes encephalitis in humans and laboratory rodents. A variant virus (V22) selected with a monoclonal antibody against the large (G1) glycoprotein showed diminished neuroinvasiveness after peripheral inoculation. This variant has an alteration in its fusion function, requiring a lower pH for the activation of fusion and demonstrating reduced efficiency of cell-to-cell fusion of BHK-21 cultures. V22 was studied in detail following the infection by intraperitoneal or intracerebral routes in suckling, weanling, or adult CD-1 mice. It exhibited a marked reduction in its ability to replicate in striated muscle and to produce viremia; however, after intracerebral injection V22 virus replicated almost as rapidly in brain as its parent, La Crosse virus. V22 virus thus represents an example of reduced neuroinvasiveness associated with an alteration at a specific epitope of the G1 glycoprotein. This same epitope also influences the fusion activity of the glycoprotein.
Regulation of Moloney murine leukemia virus replication in chronically infected cells arrested at the G0/G1 phase
Authors: Gloger I , Arad G , Panet A
Published: January 2020

The replication of Moloney murine leukemia virus (MMuLV) in chronically infected mouse cells arrested at the G0/G1 phase of the cell cycle by different procedures was investigated. MMuLV production was inhibited in glutamine- and isoleucine (Gln-Ile)-deprived G0/G1 cells. In contrast, butyric acid treatment, which efficiently arrested the cells at the G0/G1 phase of the cell cycle, did not inhibit MMuLV production. Furthermore, the inhibition of MMuLV production caused by either Gln-Ile deprivation or by interferon (IFN) treatment was overcome by butyric acid treatment. Thus, the replication of MMuLV could be dissociated from cell proliferation. The inhibition of MMuLV production in Gln-Ile-deprived cell cultures was compared to the inhibitory effect of IFN, which is known to affect budding and release of the virus. Rates of MMuLV protein synthesis were not affected in both the IFN-treated and Gln-Ile-deprived cells. However, processing of the viral polyprotein Pre65gag into p30 was blocked in the Gln-Ile-deprived cells. Furthermore, whereas in IFN-treated cells, MMuLV accumulated on the cell surface and could be released upon treatment with trypsin, in Gln-Ile-deprived cells, no virions were released by such treatment. These results indicate that in cells arrested by Gln-Ile deprivation, MMuLV is inhibited at a posttranslation step. This step appears to precede the anti-MMuLV block induced by IFN.
Competitive inhibition by human sera of mouse monoclonal antibody binding to glycoproteins C and D of herpes simplex virus types 1 and 2
Authors: Ross C , Glorioso J , Sacks S , Lavery C , Rawls W E
Published: January 2020

A competitive enzyme-linked immunosorbent assay was used to test for human antibodies to antigenic sites on herpes simplex virus (HSV) glycoproteins C and D, which are recognized by mouse monoclonal antibodies. Antibodies capable of blocking the monoclonal antibodies were detected in the human sera, and the inhibition of binding correlated with the histories of herpetic infections. The binding of monoclonal antibody to glycoprotein C of HSV type 2 was inhibited primarily by sera from patients with recurrent herpes genitalis; however, the binding of the monoclonal antibodies to gC of HSV type 1 was inhibited by sera from patients previously infected with either HSV type 1 or HSV type 2. The observations suggest that the antigenic sites defined by the mouse monoclonal antibodies are recognized by the human host.
Simian virus 40 small-t antigen-induced theophylline resistance is not mediated by cyclic AMP
Authors: Renz C , Rundell K
Published: January 2020

Small-t antigen of simian virus 40 renders CV-1 cells resistant to growth arrest induced by theophylline and other methylxanthines. Elevated levels of cyclic AMP are not involved in growth arrest of CV-1 cells by methylxanthines, and small-t antigen does not alter cyclic AMP levels dramatically after infection.
Site-directed mutagenesis of the simian virus 40 large T-antigen gene: replication-defective amino acid substitution mutants that retain the ability to induce morphological transformation
Authors: Peden K W , Pipas J M
Published: January 2020

We used a heteroduplex deletion loop mutagenesis procedure for directing sodium bisulfite-induced mutations to specific sites on viral or plasmid DNA to generate a series of SV40 large T-antigen point mutants. The mutations were directed to a region of the T-antigen gene, 0.5 map units, that is thought to be important for interaction of the protein with the viral origin of DNA replication. Of the 16 mutants reported here, 10 had lost the ability to replicate their DNA, and 3 others showed a reduced level of replication compared to wild type. All of the mutants tested were capable of transforming rat cells in culture by the dense focus assay. We conclude that the sequences of the early region around 0.5 map units are critical for the replication of viral DNA but not for the transformation function of T antigen.
Structure and physical map of Rhodopseudomonas sphaeroides bacteriophage RS1 DNA
Authors: Donohue T J , Chory J , Goldsand T E , Lynn S P , Kaplan S
Published: January 2020

We analyzed, by restriction endonuclease mapping and electron microscopy, the genome of the lytic Rhodopseudomonas sphaeroides-specific bacteriophage RS1 and characterized it as a linear molecule of approximately 60 to 65 kilobases. When the DNA from purified phage particles was examined by several independent methods, considerable size heterogeneity was apparent in the RS1 DNA. This size heterogeneity was concluded to be of biological origin, was independent of the specific host strain used to propagate virus, and was not due to the presence of host DNA within or nonspecifically associated with purified virions. In addition, treatment of RS1 DNA with either BAL 31 nuclease or DNA polymerase I Klenow fragment revealed that several distinct regions exist within the viral chromosome which contain free 3' hydroxyl groups. A restriction endonuclease map of the RS1 genome was constructed by using the restriction endonucleases EcoRI, ClaI, KpnI, BamHI, MluI, SmaI, and BclI; thereby allowing the positioning of some 40 restriction sites within the viral genome. The results are discussed in terms of the significance and the possible biological origin of the unique features discovered within the phage RS1 DNA.
Chemotherapy and vaccination: a possible strategy for the control of highly virulent influenza virus
Authors: Webster R G , Kawaoka Y , Bean W J , Beard C W , Brugh M
Published: January 2020

The influenza A virus [A/Chicken/Pennsylvania/1370/83 (H5N2)] that caused up to 80% mortality among chickens provided a model system for testing the efficacy of chemotherapeutic agents against highly virulent influenza virus. Amantadine and rimantadine administered in drinking water were efficacious both prophylactically and therapeutically. However, under conditions simulating natural transmission of virus, amantadine- and rimantadine-resistant viruses arose and were transmitted to other birds in contact with the infected chickens, causing mortality. Simultaneous administration of inactivated H5N2 vaccine and amantadine provided protection. Thus, chemotherapy may be useful in the treatment of a highly pathogenic influenza virus outbreak in humans or other animals when used in combination with vaccine.
Envelope gene and long terminal repeat determine the different biological properties of Rauscher, Friend, and Moloney mink cell focus-inducing viruses
Authors: Vogt M , Haggblom C , Swift S , Haas M
Published: January 2020

The nucleotide sequence of the envelope (env) gene and the long terminal repeat (LTR) of an infectious clone of Rauscher mink cell focus-inducing (R-MCF) virus has been determined and compared with the published env gene and LTR sequences of Friend (F)- and Moloney (M)-MCF viruses. The sequence shows that R-MCF virus, like other MCF viruses, is a recombinant virus. Its env gene contains sequences which were acquired from an env gene in the mouse genome and which confer on the MCF virus its dualtropic host range. Unlike F-MCF and M-MCF viruses, R-MCF virus will not replicate in NIH 3T3 cells. The deduced amino acid sequence for the gp70 of R-MCF differs from that of F- and M-MCF viruses by 15 amino acids between residues 49 and 138 of gp70. These differences in amino acid sequences may be responsible for the inability of R-MCF virus to replicate in NIH 3T3 cells. The host range of two hybrid viruses constructed in vitro is consistent with this hypothesis. R-MCF virus and Friend murine leukemia virus (F-MLV) show 98% identity in their env gene 3' from the acquired env sequences. This contrasts with 82% identity between the env gene of R-MCF virus and M-MLV. The LTR of R-MCF shows 98% identity with the LTR of F-MCF as compared to 88% identity with the LTR of M-MCF. This striking similarity between the sequences of R-MCF, F-MCF, and F-MLV is surprising since the Rauscher virus and the Friend virus are thought to have originated independently. The high degree of similarity suggests that Rauscher and Friend viruses have a common origin. In contrast to M-MLV, which induces predominantly a lymphoid disease, R- and F-MCF viruses induce an erythroproliferative disease in NIH Swiss mice. A hybrid R-MCF virus with a genome derived primarily from R-MCF virus and a 3' end including the U3 region derived from M-MLV induces a lymphoid disease instead of an erythroid disease. This result indicates that it is the U3 region which determines the tissue specificity of the MCF virus-induced disease. It is suggested that the putative viral enhancers in the U3 region play two roles in the process of leukemogenesis: in the Friend and Rauscher disease, the viral enhancers act by increasing the transcription of the MCF env gene; in the thymic lymphoma, the enhancers activate mainly the expression of cellular genes.
Rapid induction of hemopoietic neoplasms in newborn mice by a raf(mil)/myc recombinant murine retrovirus
Authors: Rapp U R , Cleveland J L , Fredrickson T N , Holmes K L , Morse H C , Jansen H W , Patschinsky T , Bister K
Published: January 2020

3611 MSV, a raf oncogene-transducing murine retrovirus, induced fibrosarcomas in newborn mice after a latency of 4 to 8 weeks. In contrast, newly constructed recombinant murine retroviruses carrying the myc oncogene did not induce tumors before greater than or equal to 9 weeks. A combination of both oncogenes in an infectious murine retrovirus induced hematopoietic neoplasms in addition to less prominent fibrosarcomas and pancreatic acinar dysplasia 1 to 3 weeks after inoculation. The hematological neoplasms consisted of immunoblastic lymphomas of T- and B-lineage cells and erythroblastosis. Cell lines from these tumors could be readily established in culture in regular medium, whereas culture of cells from raf oncogene-induced tumors required the addition of interleukin 3. In parallel to the synergistic action of both oncogenes on hematopoietic cells in vivo, we found that raf oncogene-induced transformation of fibroblast cell lines in culture was enhanced by the addition of myc, which by itself did not morphologically transform these permanent cell lines. We conclude that concomitant expression of raf and myc oncogenes in hematopoietic cells and fibroblastic cell lines enhances their respective transforming activities.
Deletion mutants of Bacillus subtilis bacteriophage SP beta
Authors: Spancake G A , Hemphill H E
Published: January 2020

The central portion of the chromosome of temperate Bacillus subtilis bacteriophage SPB was found to contain a region in which large deletions occurred, sometimes at high frequency. Most of the deletions could be placed into one of three groups, del1, del3, and del4, which were missing 11.8, 14.2, and 14 kilobase pairs of DNA, respectively. The chromosomal positions of the three types of deletions overlapped and together defined a continuous region of 27 kilobase pairs surrounding the prophage attachment site attPSPB. The 27-kilobase-pair segment contained no functions required for lytic growth of the phage, but DNA within this region was used as a template for RNA synthesis at several stages in the life cycle of SPB. In addition the transcription of DNA during lytic infection was found to be initiated over a large portion of one-half of the viral chromosome (the arbitrary left half). Subsequently, the synthesis of early RNA was terminated as late transcription continued on the opposite side of the chromosome.
Identification and characterization of the Epstein-Barr virus receptor on human B lymphocytes and its relationship to the C3d complement receptor (CR2)
Authors: Nemerow G R , Wolfert R , McNaughton M E , Cooper N R
Published: January 2020

In pursuing studies on the early events in the infection of human B cells by Epstein-Barr virus (EBV), we examined the host cell attachment phase with a panel of B-cell-specific monoclonal antibodies. One of the monoclonal antibodies, OKB7, directly blocked the attachment of purified EBV to B lymphocytes in the absence of a second anti-immunoglobulin antibody and thereby prevented EBV infection of tonsil and peripheral blood B cells. Although earlier studies have shown a close association of the EBV and complement receptor (CR2), an anti-CR2 monoclonal antibody, anti-B2, did not directly block the binding of EBV to B cells. A comparison of the structures recognized by these monoclonal antibodies on various cell types and their functional and physiochemical properties was undertaken. Flow cytometric analysis revealed that the molecules detected by OKB7 and anti-B2 were coexpressed to the same extent on B cells but were not expressed on T-cell lines. OKB7 and anti-B2 both immunoprecipitated a 145,000-molecular-weight membrane protein with an isoelectric point of 8.2 from membrane extracts of Raji lymphoblastoid cells. OKB7 and, to a lesser extent, anti-B2 directly blocked the attachment of C3d,g-coated fluorescent microspheres and sheep erythrocytes bearing C3d to B cells, indicating that these antibodies also react with CR2. These studies indicate that the EBV-CR2 receptor is a single membrane glycoprotein which possesses multiple antigenic and functional epitopes.
Establishment of latency in mice by herpes simplex virus 1 recombinants that carry insertions affecting regulation of the thymidine kinase gene
Authors: Sears A E , Meignier B , Roizman B
Published: January 2020

Herpes simplex virus 1 recombinants carrying alpha-, beta-, and late gamma (gamma 2)-regulated thymidine kinase (TK) genes were tested for the ability to establish latency in BALB/c mice inoculated by the eye route. The significant findings were as follows. Representatives of alpha- and gamma 2-regulated TK recombinants all established and maintained latent infections, but the efficiency was somewhat lower than that of wild-type virus. Of the three alpha TK recombinants tested, one (R316) spontaneously deleted portions of the inserted sequences which conferred alpha regulation to the TK gene. The viruses carrying these deletions expressed considerably lower TK activity than did wild-type virus, i.e., 2 to 40% of the levels expressed by the wild-type virus carrying the beta TK gene. However, the ability of these viruses to establish latency was not related to the efficiency of expression of the TK gene. These results indicate the following: (i) conversion of the TK gene into an alpha or gamma 2 gene did not preclude the establishment of latent infections; (ii) there was no correlation between the levels of TK activity expressed in cell culture and the ability to establish latency; and (iii) rearrangement of the genome by insertions or deletions which interrupt gene domains did not automatically result in an inability to establish latent infections.
Degradation of cellular mRNAs induced by a virion-associated factor during herpes simplex virus infection of Vero cells
Authors: Schek N , Bachenheimer S L
Published: January 2020

We have used Northern blot hybridization to study the accumulation of specific cellular mRNAs in Vero cells infected with herpes simplex virus (HSV) type 1 or type 2. HSV-1 infection decreased the cytoplasmic levels of beta- and gamma-actin, beta-tubulin, and histone H3 and H4 mRNAs, though not all at the same rate. HSV-2 infection resulted in a more rapid decrease in actin and histone mRNA levels compared with HSV-1 infection. The turnover rate of each type of mRNA studied was accelerated in HSV-infected cells compared with the rate in uninfected cells. Cellular mRNA degradation was induced by HSV infection under conditions of (i) inhibition of de novo protein synthesis, (ii) inhibition of de novo RNA synthesis, (iii) infection with HSV-1(17) tsK, which fails to produce early and late viral gene products at the nonpermissive temperature, and (iv) infection with purified virions in the presence of actinomycin D. We have concluded that, in Vero cells, cellular mRNA degradation is induced by a factor associated with the infecting HSV virion and thus does not require de novo RNA or protein synthesis. Despite the overall inhibition of cellular mRNA accumulation, a novel 2.2-kilobase cytoplasmic actin transcript was produced in HSV-infected cells when viral gene expression was allowed. The level of accumulation of cytoplasmic host mRNAs was compared with the rate of cellular protein synthesis under different conditions of infection. This analysis suggests that both HSV-1 and HSV-2 require an additional function(s) to completely inhibit cellular protein synthesis.
Susceptibility to erbB-induced erythroblastosis is a dominant trait of 151 chickens
Authors: Robinson H L , Miles B D , Catalano D E , Briles W E , Crittenden L B
Published: January 2020

Rous-associated virus-1 (RAV-1)-induced erythroblastosis results from proviral insertions into or viral transductions of the c-erbB region of the epidermal growth factor gene. Most chickens develop low incidences (less than 5%) of RAV-1-induced erythroblastosis. However, an inbred line of chickens (151) suffers high incidences (approximately 80%) of RAV-1-induced erythroblastosis. Analysis of 151, K28, and (K28 X 151) X K28 chickens for susceptibility to RAV-1-induced erythroblastosis revealed that susceptibility to RAV-1-induced erythroblastosis is a dominant trait of line 151 chickens. Analysis of 151 X K28 and K28 chicks for susceptibility to the induction of erythroblastosis by two new c-erbB-transducing viruses (avian erythroblastosis virus strains AEV-5005 and AEV-5009) revealed that susceptibility to transformation by new c-erbB-transducing viruses is also a dominant trait of 151 chickens. We think it is likely that both of these dominant traits are encoded by the same gene or genes. Our hypothesis is that this gene (or genes) potentiates the ability of the transmembrane and cytoplasmic domains of the epidermal growth factor receptor to transform cells.
trans-Activation of the human T-cell leukemia virus long terminal repeat correlates with expression of the x-lor protein
Authors: Sodroski J G , Goh W C , Rosen C A , Salahuddin S Z , Aldovini A , Franchini G , Wong-Staal F , Gallo R C , Sugamura K , Hinuma Y
Published: January 2020

Cell lines established directly from adult T-cell leukemia-lymphoma patients or immortalized by human T-cell leukemia virus type I (HTLV-I) in vitro that do not produce complete HTLV virions were characterized both for the content of viral proteins and for the presence of trans-acting factors activating gene expression under the control of the HTLV long terminal repeat. The expression of the 42-kilodalton HTLV x-lor product correlated with trans-activation of the long terminal repeat. The implications of this study for understanding the role of the HTLV x-lor product in the initiation and maintenance of T-lymphocyte transformation are discussed.
Tissue selectivity of murine leukemia virus infection is determined by long terminal repeat sequences
Authors: Rosen C A , Haseltine W A , Lenz J , Ruprecht R , Cloyd M W
Published: January 2020

Here we show that the tissue specificity of murine retrovirus infections is determined by the long terminal repeat (LTR) of an otherwise isogenic set of viruses. The isogenic viruses used for this study contain the coding gag, pol, and env genes of the avirulent Akv virus. Recombinant viruses that contain the LTR of a virus that induces T-cell leukemia lymphoma preferentially infect T lymphocytes. Viruses that carry the LTR of a virus that induces erythroleukemia preferentially infect non-T lymphoblastoid cell lines in the marrow and spleen. The Akv virus itself displays no tissue preference for hematopoietic cells. These experiments suggest that retroviruses that carry appropriate enhancer-promoters can be used to infect selectively specific target cells in animals.
Use of site-specific antipeptide antibodies to perturb the serine kinase catalytic activity of p37mos
Authors: Maxwell S A , Arlinghaus R B
Published: January 2020

The mos oncogene of Moloney murine sarcoma virus encodes a protein of approximately 37,000 daltons (designated p37mos). We have detected a serine protein kinase activity which is closely associated with p37mos in immune complexes obtained with antibodies [anti-mos(37-55) serum] that were generated with a peptide containing amino acids 37 through 55 of the v-mos protein (S. A. Maxwell and R. B. Arlinghaus, Virology 143:321-333, 1985). Immune complexes that were derived with antibodies generated against peptides representing the C-terminal 8 or 12 amino acids of v-mos (anti-C2 and anti-C3 serum, respectively) exhibited very little kinase activity capable of phosphorylating p37mos. Treatment of anti-mos(37-55) complexes containing active v-mos kinase with anti-C3 or anti-C2 serum resulted in a dramatic reduction of the in vitro phosphorylation of p37mos. Antiserum blocked with the appropriate C-terminal peptide had no inhibitory effect on the phosphorylation of p37mos in anti-mos(37-55) complexes which indicated that the inhibition of v-mos kinase activity was a specific effect of these antibodies. The specific inhibition of the in vitro phosphorylation of p37mos by antibodies directed against the C terminus of the v-mos protein provides strong evidence that the v-mos gene encodes a serine protein kinase. In addition, the extreme C terminus of p37mos may be critical for an active v-mos kinase.
Chromosomal assignment of two endogenous ecotropic murine leukemia virus proviruses of the AKR/J mouse strain
Authors: Taylor B A , Rowe L , Jenkins N A , Copeland N G
Published: January 2020

The AKR/J mouse strain is genetically fixed for three different ecotropic murine leukemia virus genomes, designated Akv-1, Akv-3, and Akv-4 (Emv-11, Emv-13, and Emv-14). With recombinant inbred strains and crosses with linkage-testing stocks, Akv-3 and Akv-4 were placed on the mouse chromosome map. Akv-3, which encodes a replication-defective provirus, maps near the agouti coat color locus, a, on chromosome 2. Akv-4, which is replication competent, maps near the neurological mutant gene locus trembler, Tr, on chromosome 11. Akv-1 and Akv-2 (Emv-12), an ecotropic provirus carried by AKR/N but not AKR/J, have previously been mapped to chromosome 7 and 16, respectively. Thus, the four Akv proviruses mapped to date are on four different chromosomes. Akv-3 is the second ecotropic murine leukemia virus provirus to be mapped near the agouti locus. The results are discussed in relation to possible nonrandomness of viral integration.
Virus-induced modification of the host cell is required for expression of the bacterial chloramphenicol acetyltransferase gene controlled by a late herpes simplex virus promoter (VP5)
Authors: Costa R H , Draper K G , Devi-Rao G , Thompson R L , Wagner E K
Published: January 2020

The requirements for expression of genes under the control of early (alkaline exonuclease) and late (VP5) herpes simplex virus type 1 (HSV-1) gene promoters were examined in a transient expression assay, using the bacterial chloramphenicol acetyltransferase gene as an expression marker. Both promoters were induced, resulting in the production of high levels of the enzyme upon low-multiplicity infection by HSV-1. S1 nuclease analysis of hybrids between RNA isolated from infected cells containing HSV-1 promoter constructs and marker gene DNA demonstrated normal transcriptional initiation of the marker gene directed by the viral promoters. Viral DNA sequences no more than 125 bases 5' of the putative transcriptional cap site were sufficient for maximum activity of the late promoter. In contrast to expression controlled by the early gene, the late promoter was not active at a measurable level in uninfected cells until DNA sequences between 75 and 125 bases 5' of the transcriptional cap site were deleted. Cotransfection of cells with the expression marker controlled by HSV promoters and a cosmid containing HSV alpha (immediate-early) genes indicated that full expression of both early and late promoters requires the same virus-induced host cell modifications. Inhibition of viral DNA synthesis results in an increased rate of transient expression of marker genes under control of either early or late promoters in contrast to the situation in normal virus infection. These data provide evidence that the normal course of expression of late HSV genes involves negative modulation of potentially active promoters in the infected cell.
Biologically active proviral clone of myeloblastosis-associated virus type 1: implications for the genesis of avian myeloblastosis virus
Authors: Perbal B , Lipsick J S , Svoboda J , Silva R F , Baluda M A
Published: January 2020

A biologically active myeloblastosis-associated virus (MAV) provirus was cloned from a bacteriophage recombinant library constructed from leukemic chicken myeloblast DNA. The restriction endonuclease map of this clone was consistent with that of a type 1 MAV (MAV-1). Interference assays of virus recovered from cultured chicken embryo fibroblasts after DNA transfection established that the provirus was infectious and confirmed that it belonged to avian retrovirus subgroup A (type 1). Antipeptide antibodies raised against the env-encoded carboxyl terminus of p48myb, the transforming protein of avian myeloblastosis virus, specifically immunoprecipitated the gp37env from quail cells transfected with MAV-1 proviral DNA but not from cells infected with MAV-2. This suggests that MAV-1 rather than MAV-2 is the progenitor helper virus from which avian myeloblastosis virus arose by the transduction of cellular proto-oncogene sequences.
Identification by immunobinding assay of the polypeptide coded by the DNA polymerase gene of bacteriophage T5 and its amber mutants and the direction of transcription of the gene
Authors: Schneider S S , Roop B C , Fujimura R K
Published: January 2020

We identified by immunobinding assay the polypeptides synthesized as the result of amber mutations in the DNA polymerase gene of bacteriophage T5. Comparison of the size of such polypeptides revealed the order of mutagenic loci of these mutations and the direction of transcription of the gene. Extracts of cells infected with wild-type T5 and with five amber mutants of the polymerase gene (D7, D8, D9, am1, and am6) were prepared, and the proteins were resolved by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. After transfer of the proteins to a nitrocellulose sheet, a radioimmunolabeling technique was used to identify the T5 DNA polymerase and its amber mutant polypeptides. Based on the relative sizes of the polypeptides, the transcription of the T5 DNA polymerase gene was determined to proceed in the order D7, D8, am1, D9, and am6. The molecular weights of the DNA polymerase polypeptides coded by D8, am1, D9, am6, and T5+ were 23,000, 45,000, 75,000, 83,000, and 96,000, respectively. The D7-coded polypeptide was not detectable. These data suggest that the carboxyl-terminal region of the enzyme is essential for the polymerase function.
Primary structure of p19 species of avian sarcoma and leukemia viruses
Authors: Vogt V M , Pepinsky R B , Southard L E
Published: January 2020

The internal structural proteins of avian sarcoma and leukemia viruses are derived from a precursor polypeptide that is the product of the viral gag gene. The N-terminal domain of the precursor gives rise to p19, a protein that interacts with the lipid envelope of the virus and that may also interact with viral RNA. The C terminus of p19 from the Prague C strain of Rous sarcoma virus was previously assigned to a tyrosine residue 175 amino acids from the N terminus. We have used metabolic labeling and carboxypeptidase digestion to show that the C terminus of p19 is actually tyrosine 155. This implies the existence of a sixth gag protein 22 amino acids in length and located between p19 and p10 on the gag precursor. The p19 species of some recombinant avian sarcoma viruses and of the defective endogenous virus derived from the ev-1 locus migrate on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as if they were about 4,000 daltons smaller than p19. We have elucidated the structure of these forms, called p19 beta, by analysis of the proteins and determination of the DNA sequence of the p19 region of the gag gene from ev-1 and ev-2. Esterification of carboxyl groups completely suppressed the differences in migration of p19 and p19 beta. Peptide mapping showed the altered mobility to be determined by sequences in the C-terminal cyanogen bromide fragment of the proteins. We conclude from the DNA sequence that a single glutamate-lysine alteration is responsible for the altered electrophoretic mobility.
Molecular cloning and nucleotide sequence of deer papillomavirus
Authors: Groff D E , Lancaster W D
Published: January 2020

The genome of deer papillomavirus (DPV) isolated from American white-tailed deer was cloned into pBR322, and the entire nucleotide sequence of 8,374 base pairs was determined. The overall genetic organization of the DPV genome was similar to that of other papillomaviruses. All significant open reading frames were located on one strand, and the locations of putative promoters and polyadenylation signals were similar to those identified in the closely related bovine papillomavirus type 1 (BPV-1) genome. The DPV genome was approximately colinear with BPV-1 except for a noncoding region separating the early and late regions. The regions of highest nucleotide sequence homology between DPV and BPV-1 were found in the E1 open reading frame coding for BPV-1 DNA replication function and in the L1 open reading frame, which encodes the major capsid protein of BPV-1.