Solon Rhode - Academia.edu (original) (raw)

Papers by Solon Rhode

Research paper thumbnail of DNA sequence of the 5' terminus containing the replication origin of parvovirus replicative form DNA

Journal of Virology, Mar 1, 1982

Research paper thumbnail of DNA double-strand break repair functions defend against parvovirus infection

Journal of Virology, Sep 1, 1996

We measured parvovirus replication and sensitivity to X-ray damage in nine CHO cell lines represe... more We measured parvovirus replication and sensitivity to X-ray damage in nine CHO cell lines representing a variety of DNA repair deficiencies. We found that parvovirus replication efficiency increases with radiosensitivity. Parvovirus replication is disrupted at an early stage of infection in DNA repair-proficient cells, before conversion of the single-stranded viral DNA genome into the double-stranded replicative form. Thus, status of the DNA repair machinery inversely correlates with parvovirus replication and is proportional to the host's ability to repair X-ray-induced damage.

Research paper thumbnail of Parvovirus replication in normal and transformed human cells correlates with the nuclear translocation of the early protein NS1

Journal of Virology, 1989

Research paper thumbnail of Replication Process of the Parvovirus H-1 III. Factors Affecting H-1 RF DNA Synthesis

Journal of Virology, Oct 1, 1974

Research paper thumbnail of Minocycline and rifampin: proposed treatment regimen for the elimination of meningococci from the nasopharynges of healthy carriers

Research paper thumbnail of Encapsidation of a recombinant LuIII parvovirus genome by H1 virus and the fibrotropic or lymphotropic strains of minute virus of mice

Journal of General Virology, Jun 1, 1993

Research paper thumbnail of Inhibition of 7,12-dimethylbenz(a)anthracene-induced tumors in Syrian hamsters by prior infection with H-1 parvovirus

PubMed, Jul 1, 1982

Hamsters, given injections s.c. at birth of H-1 parvovirus and 1 month later given a single injec... more Hamsters, given injections s.c. at birth of H-1 parvovirus and 1 month later given a single injection of 7,12-dimethylbenz(a)anthracene, had a 38% tumor incidence compared with a 95% incidence in animals receiving 7,12-dimethylbenz(a)anthracene alone. Thus, H-1 which, it has already been shown, invokes a resistance to the incidence of spontaneous and adenovirus-induced neoplasms in hamsters also produces a suppression of a carcinogen-induced tumor in these animals; this suggests that the H-1-induced barrier to successful oncogenesis by these diverse agents has a common mechanism which, present experiments indicate, is not related to a positive or negative H-1 serology. The pathology of the 7,12-dimethylbenz(a)anthracene-induced tumors was similar for both control and H-1-infected hamsters. Although all but one of the primary neoplasms were anaplastic fibrosarcomas as reported previously by others, 25% of the affected females had, in addition, mammary adenocarcinomas, an extremely rare tumor in hamsters.

Research paper thumbnail of Nonstructural protein NS2 of parvovirus H-1 is required for efficient viral protein synthesis and virus production in rat cellsin vivo andin Vitro

Virology, Sep 1, 1991

We generated a mutation in the gene for the nonstructural protein NS2 of parvovirus H-1 in which ... more We generated a mutation in the gene for the nonstructural protein NS2 of parvovirus H-1 in which the highly conserved dinucleotide AG at the r splice acceptor site of NS2 intron I was mutated to CG. The nadselon don not change the amino acid sequence for NS1. The splice acceptor (SA) mutant gene was introduced Wft the 144 virus (H-ISA) end an infectious done of Will (pt-uHI SA). The R2 transcripts encoding NS2 were absent by both Northern blot and primer extension analysis in the LuH1 SA or H-1 SA virus-infected calls and the NS2 protein was undetectable in the infected cell lysate by immunoprecipitation. These NS2 null mutant viruses were capable of lytc growth in, Coll lines that were derived from human, hamster, and dog, but they produced lower virus titers than w e H-1. The H-1 SA virus nonproductively infected Rat2 rat fibroblasts and transformed Rst2 cell lines. Ans"Is of synchronized infections of rat f b obits demonstrated that H-1 SA viral duplex replicative form DNA replication wee lathered and that single-stranded progeny DNA was deficient compared to wild-type H-1. In addition, H-1 SA viral protein was about 10% of wild-type virus and virions were not detectable in rat fibroblests. However, H-1 SA rt MRI wall R3 accumulated to wild-type levels. NS2 was also required for productive infection in newborn rats but rat fn-newborn hamsters. These results indicate that NS2 plays an important role in the regulation of viral protein synthesis in rat cells in vivo and in vitro. 01991 Academic Press, Inc .

Research paper thumbnail of Both excision and replication of cloned autonomous parvovirus DNA require the NS1 (rep) protein

Journal of Virology, Oct 1, 1989

When a bacterial plasmid containing the entire genome of LullI virus except for the terminal 18 n... more When a bacterial plasmid containing the entire genome of LullI virus except for the terminal 18 nucleotides from the right end is transfected into HeLa cells, the viral DNA is rescued and replicated, with production of infectious virus. This experimental system was used to examine the viral proteins and cis elements required for the excision and replication of viral DNA. The deletion of the entire NS1 gene provided a viral genome that was excised from the plasmid and replicated only when an NS1 gene was provided in trans. A frameshift mutation in the NS2 intron that truncates NS1 prevented excision and replication. Deletion of the left-end terminal inverted repeat or the right-end inverted repeat prevented excision of viral DNA from that end but not from the wild-type terminus. The viral terminus excised from the plasmid was protected from a processive degradation process, which began on the vector portion of the plasmid. The inhibitor of DNA polymerases a and 8, aphidicolin, blocked the excision reaction.

Research paper thumbnail of Parvovirus genome: nucleotide sequence of H-1 and mapping of its genes by hybrid-arrested translation

Journal of Virology, 1983

The nucleotide sequence of the parvovirus H-1 has been determined by the chain-terminating method... more The nucleotide sequence of the parvovirus H-1 has been determined by the chain-terminating method of Sanger. The sequence is 5,176 nucleotides long. Two large open reading frames (1 and 2) and two smaller open reading frames (3 and 4) of potential importance were identified in the plus-strand sequence. Promoter sequences are located at map positions 4 and 38 when map positions are expressed as percent of genome length from the 3' end of the virion minus strand. The locations for the genes for the parvovirus capsid proteins and a 76,000-dalton noncapsid protein (NCVP1) were mapped by hybrid-arrested translation. The gene for the capsid proteins VP1 and VP2' is located in the 5' half of the virus genome. The gene for NCVP1 is located in the 3' half of the viral DNA.

Research paper thumbnail of Relationship of Serogroups of Neisseria meningitidis II. R Variants of Neisseria meningitidis

Infection and Immunity, 1972

Meningococci isolated in primary cultures from nasopharyngeal carriers occasionally consisted of ... more Meningococci isolated in primary cultures from nasopharyngeal carriers occasionally consisted of mixtures of smooth (S) and rough (R) strains. The R strains were separated from the S strains and their morphological and serological characteristics were studied. Some of these R strains reverted spontaneously to S strains which subsequently produced group-specific polysaccharide. Several R strains, grown in the presence of deoxyribonucleic acid from either an R strain of known parentage or an S strain, formed recombinants with serological group specificity. MATERIALS AND METHODS Strins. Strain M60 of Neisseria meningitidis was

Research paper thumbnail of Trans-activation of H-1 parvovirus P38 promoter is correlated with increased binding of cellular protein(s) to the trans-activation responsive element (tar)

Virology, Sep 1, 1992

The parovivirus H-l P38 promoter contains a trans-activation responsive element (tar). It was pre... more The parovivirus H-l P38 promoter contains a trans-activation responsive element (tar). It was previously shown that the parvovirus H-l nonstructural protein NSl positively regulates the expression of the P38 promoter for the viral capsid protein gene via the tar (Rhode and Richard, 1987,J. Viral. 61, 2807-2815). To characterize the mechanism of trans-activation by the tar, we used gel shift assays to demonstrate that there exist proteins in virus-infected cellular extracts which have higher binding activity than that found in mock-infected extracts. These observations in vitro are consistent with the expression by P38 constructs with the wild-type promoter linked to a reporter gene, chloramphenicol acetyl transferase (cat), in viva. We also provide evidence that the protein(s)-tar complex has a molecular mass of approximately 75 kDa in an SDS-polyacrylamide gel, which is less than NSl, and this complex cannot be precipitated by NSl antibody, which suggests that NSl mediates the trans-activation by inducing an alteration in the binding activity of some cellular protein(s) in an indirect manner. These data support our previous hypothesis for the activation of the P38 promoter, in which the trans-activator(s) interacts with the tar effectively in the presence of NSl, leading to the formation of the transcription initiation complex by protein-protein associations (Gu, Chen, and Rhode, 1992, Virology 187, 1 O-l 7).

Research paper thumbnail of Ultrastructural Studies of H-1 Parvovirus Replication VI. Simultaneous Autoradiographic and Immunochemical Intranuclear Localization of Viral DNA Synthesis and Protein Accumulation

Journal of Virology, 1978

Research paper thumbnail of The Effect of Coumermycin A1on the Meningococcal Carrier State

The American Journal of the Medical Sciences, Sep 1, 1970

Research paper thumbnail of Replication process of the parvovirus H-1. IX. Physical mapping studies of the H-1 genome

Journal of Virology, May 1, 1977

Research paper thumbnail of Replication Process of the Parvovirus H-1 II. Isolation and Characterization of H-1 Replicative Form DNA

Journal of Virology, Feb 1, 1974

Research paper thumbnail of Evaluation of Group C Meningococcal Polysaccharide Vaccine in Marine Recruits, San Diego, CALIFORNIA1

American Journal of Epidemiology, Jul 1, 1970

Group C meningococcal polysaccharide vaccine was well tolerated by 3,018 vaccinated Marine recrui... more Group C meningococcal polysaccharide vaccine was well tolerated by 3,018 vaccinated Marine recruits. The vaccine appeared to be groupspecific since it prevented the acquisition of only group C meningococci. The vaccine stimulated a good hemagglutinating antibody response, but did not stimulate a comiplement fixing antibody response. One systemic illness of uncertain etiology, possibly vaccine related, vw observed among the vaccinees. That the vaccine affords protect ion against clinical disease was suggested when three cases of meningococcal disease of group C etiology developed in the nonvaccinated controls thile none occurred among the vaccinated men of the study population. Reproduced by NATIONAL TECHNICAL INFORMATION SERVICE U S Departm~ent of Conmmerce Springfied VA 22151 DD14 34 UNCLASSIPIED Seernity Clsfle"maoe Reproduced by permission of The Williams & Wilkins Company. Further reproduction prohibited.

Research paper thumbnail of Replication process of the parvovirus H-1 V. Isolation and characterization of temperature-sensitive H-1 mutants

Journal of Virology, Feb 1, 1976

Two temperature-sensitive mutants of the parvovirus H-1 have been isolated and characterized. The... more Two temperature-sensitive mutants of the parvovirus H-1 have been isolated and characterized. These mutants are distinguishable by the immunofluorescent

Research paper thumbnail of Ultrastructural studies of H-1 parvovirus replication. V. Immunocytochemical demonstration of separate chromatin-associated and inclusion-associated antigens

Journal of Virology, Oct 1, 1977

Electron microscopy and immunocytochrome c staining were used to define the phenotypes of several... more Electron microscopy and immunocytochrome c staining were used to define the phenotypes of several temperature-sensitive (ts) H-1 mutants. They were classified into three separate groups based on the properties of their capsids at the restrictive temperature (rT): (class 1) ts2 did not assemble capsids but produced spherical and irregular amorphous inclusions; (class 2) tsl and ts7 exclusively synthesized empty particles which all aggregated and crystallized; and (class 3) ts8 and ts1O formed noncrystalline aggregates of empty virions, but many individual full, as well as empty, capsids were associated with euchromatin. Synthesis of progeny DNA and hemagglutinin at rT were normal for class 3 mutants, but defective for those in classes 1 and 2. The immunospecific staining patterns of these mutants indicated that the H-1 capsid proteins probably form two separate intranuclear antigens: (i) a thermostable chromatin-associated antigen present in proteins that have not formed capsids and are concentrated on heterochromatin and nucleolar-associated chromatin and (ii) a thermolabile inclusion-associated antigen found in the proteins of assembled empty capsids that compose H-1 inclusions. H-1 is a small (25 nm) icosahedral parvovirus (3) requiring the late Sor G2-phase of the host cell cycle for replication (7). Its single-stranded DNA has a molecular weight of about 1.6 x 106 (15) and codes for only two viral capsid polypeptides (VP1 and VP2') in vivo (4). Very similar capsid components are present in the parvovirus minute virus of mice (18), and it appears that the amino acid sequence of VP2' is contained within VP1, the larger polypeptide (19). Studies on parvovirus transcriptional capacities show that a single mRNA capable of coding for only VP1 is made by adenovirus-associated virus (2) and by Kilham rat virus (10). Also, many different temperature-sensitive (ts) mutants of H-1 have been isolated in our laboratory, and the six that have been tested failed to show complementation, implying that the mu

Research paper thumbnail of Ultrastructural studies of H-1 parvovirus replication. IV. Crystal development and structure with the temperature-sensitive mutant ts1

Journal of Virology, Oct 1, 1977

Electron microscopy was used to study the development and structure of viral crystals of ts 1, a ... more Electron microscopy was used to study the development and structure of viral crystals of ts 1, a temperature-sensitive mutant of H-1 parvovirus. At early times postinfection, at the restrictive temperature, empty H-1 capsids aggregated to form conspicuous noncrystalline conglomerates in human NB cell nuclei; these particles did not associate with euchromatin as in wild-type H-1 infections. Later on, the capsid aggregates appeared to form polycrystals exhibiting rodlike, hexagonal, and cubic patterns that were interconvertible using a goniometer specimen stage. The unit cell of this crystal was cubic, consisted of 16 empty particles, and measured 50 nm on each side. Full particles made at the permissive temperature were never observed under restrictive conditions. Experiments in which cultures were shifted from the permissive to the restrictive temperature showed that full virions were not incorporated into crystals. The crystals dissociated into individual particles when changes were made from restrictive to permissive conditions. Correlations between the formation of crystals at the restrictive temperature, their dissociation into capsid components after shifting from the restrictive to the permissive state, and the extent of host cell damage were also observed. Possible roles of cellular functions in regulating tsl H-1 polycrystal assembly and dissociation are discussed.

Research paper thumbnail of DNA sequence of the 5' terminus containing the replication origin of parvovirus replicative form DNA

Journal of Virology, Mar 1, 1982

Research paper thumbnail of DNA double-strand break repair functions defend against parvovirus infection

Journal of Virology, Sep 1, 1996

We measured parvovirus replication and sensitivity to X-ray damage in nine CHO cell lines represe... more We measured parvovirus replication and sensitivity to X-ray damage in nine CHO cell lines representing a variety of DNA repair deficiencies. We found that parvovirus replication efficiency increases with radiosensitivity. Parvovirus replication is disrupted at an early stage of infection in DNA repair-proficient cells, before conversion of the single-stranded viral DNA genome into the double-stranded replicative form. Thus, status of the DNA repair machinery inversely correlates with parvovirus replication and is proportional to the host's ability to repair X-ray-induced damage.

Research paper thumbnail of Parvovirus replication in normal and transformed human cells correlates with the nuclear translocation of the early protein NS1

Journal of Virology, 1989

Research paper thumbnail of Replication Process of the Parvovirus H-1 III. Factors Affecting H-1 RF DNA Synthesis

Journal of Virology, Oct 1, 1974

Research paper thumbnail of Minocycline and rifampin: proposed treatment regimen for the elimination of meningococci from the nasopharynges of healthy carriers

Research paper thumbnail of Encapsidation of a recombinant LuIII parvovirus genome by H1 virus and the fibrotropic or lymphotropic strains of minute virus of mice

Journal of General Virology, Jun 1, 1993

Research paper thumbnail of Inhibition of 7,12-dimethylbenz(a)anthracene-induced tumors in Syrian hamsters by prior infection with H-1 parvovirus

PubMed, Jul 1, 1982

Hamsters, given injections s.c. at birth of H-1 parvovirus and 1 month later given a single injec... more Hamsters, given injections s.c. at birth of H-1 parvovirus and 1 month later given a single injection of 7,12-dimethylbenz(a)anthracene, had a 38% tumor incidence compared with a 95% incidence in animals receiving 7,12-dimethylbenz(a)anthracene alone. Thus, H-1 which, it has already been shown, invokes a resistance to the incidence of spontaneous and adenovirus-induced neoplasms in hamsters also produces a suppression of a carcinogen-induced tumor in these animals; this suggests that the H-1-induced barrier to successful oncogenesis by these diverse agents has a common mechanism which, present experiments indicate, is not related to a positive or negative H-1 serology. The pathology of the 7,12-dimethylbenz(a)anthracene-induced tumors was similar for both control and H-1-infected hamsters. Although all but one of the primary neoplasms were anaplastic fibrosarcomas as reported previously by others, 25% of the affected females had, in addition, mammary adenocarcinomas, an extremely rare tumor in hamsters.

Research paper thumbnail of Nonstructural protein NS2 of parvovirus H-1 is required for efficient viral protein synthesis and virus production in rat cellsin vivo andin Vitro

Virology, Sep 1, 1991

We generated a mutation in the gene for the nonstructural protein NS2 of parvovirus H-1 in which ... more We generated a mutation in the gene for the nonstructural protein NS2 of parvovirus H-1 in which the highly conserved dinucleotide AG at the r splice acceptor site of NS2 intron I was mutated to CG. The nadselon don not change the amino acid sequence for NS1. The splice acceptor (SA) mutant gene was introduced Wft the 144 virus (H-ISA) end an infectious done of Will (pt-uHI SA). The R2 transcripts encoding NS2 were absent by both Northern blot and primer extension analysis in the LuH1 SA or H-1 SA virus-infected calls and the NS2 protein was undetectable in the infected cell lysate by immunoprecipitation. These NS2 null mutant viruses were capable of lytc growth in, Coll lines that were derived from human, hamster, and dog, but they produced lower virus titers than w e H-1. The H-1 SA virus nonproductively infected Rat2 rat fibroblasts and transformed Rst2 cell lines. Ans"Is of synchronized infections of rat f b obits demonstrated that H-1 SA viral duplex replicative form DNA replication wee lathered and that single-stranded progeny DNA was deficient compared to wild-type H-1. In addition, H-1 SA viral protein was about 10% of wild-type virus and virions were not detectable in rat fibroblests. However, H-1 SA rt MRI wall R3 accumulated to wild-type levels. NS2 was also required for productive infection in newborn rats but rat fn-newborn hamsters. These results indicate that NS2 plays an important role in the regulation of viral protein synthesis in rat cells in vivo and in vitro. 01991 Academic Press, Inc .

Research paper thumbnail of Both excision and replication of cloned autonomous parvovirus DNA require the NS1 (rep) protein

Journal of Virology, Oct 1, 1989

When a bacterial plasmid containing the entire genome of LullI virus except for the terminal 18 n... more When a bacterial plasmid containing the entire genome of LullI virus except for the terminal 18 nucleotides from the right end is transfected into HeLa cells, the viral DNA is rescued and replicated, with production of infectious virus. This experimental system was used to examine the viral proteins and cis elements required for the excision and replication of viral DNA. The deletion of the entire NS1 gene provided a viral genome that was excised from the plasmid and replicated only when an NS1 gene was provided in trans. A frameshift mutation in the NS2 intron that truncates NS1 prevented excision and replication. Deletion of the left-end terminal inverted repeat or the right-end inverted repeat prevented excision of viral DNA from that end but not from the wild-type terminus. The viral terminus excised from the plasmid was protected from a processive degradation process, which began on the vector portion of the plasmid. The inhibitor of DNA polymerases a and 8, aphidicolin, blocked the excision reaction.

Research paper thumbnail of Parvovirus genome: nucleotide sequence of H-1 and mapping of its genes by hybrid-arrested translation

Journal of Virology, 1983

The nucleotide sequence of the parvovirus H-1 has been determined by the chain-terminating method... more The nucleotide sequence of the parvovirus H-1 has been determined by the chain-terminating method of Sanger. The sequence is 5,176 nucleotides long. Two large open reading frames (1 and 2) and two smaller open reading frames (3 and 4) of potential importance were identified in the plus-strand sequence. Promoter sequences are located at map positions 4 and 38 when map positions are expressed as percent of genome length from the 3' end of the virion minus strand. The locations for the genes for the parvovirus capsid proteins and a 76,000-dalton noncapsid protein (NCVP1) were mapped by hybrid-arrested translation. The gene for the capsid proteins VP1 and VP2' is located in the 5' half of the virus genome. The gene for NCVP1 is located in the 3' half of the viral DNA.

Research paper thumbnail of Relationship of Serogroups of Neisseria meningitidis II. R Variants of Neisseria meningitidis

Infection and Immunity, 1972

Meningococci isolated in primary cultures from nasopharyngeal carriers occasionally consisted of ... more Meningococci isolated in primary cultures from nasopharyngeal carriers occasionally consisted of mixtures of smooth (S) and rough (R) strains. The R strains were separated from the S strains and their morphological and serological characteristics were studied. Some of these R strains reverted spontaneously to S strains which subsequently produced group-specific polysaccharide. Several R strains, grown in the presence of deoxyribonucleic acid from either an R strain of known parentage or an S strain, formed recombinants with serological group specificity. MATERIALS AND METHODS Strins. Strain M60 of Neisseria meningitidis was

Research paper thumbnail of Trans-activation of H-1 parvovirus P38 promoter is correlated with increased binding of cellular protein(s) to the trans-activation responsive element (tar)

Virology, Sep 1, 1992

The parovivirus H-l P38 promoter contains a trans-activation responsive element (tar). It was pre... more The parovivirus H-l P38 promoter contains a trans-activation responsive element (tar). It was previously shown that the parvovirus H-l nonstructural protein NSl positively regulates the expression of the P38 promoter for the viral capsid protein gene via the tar (Rhode and Richard, 1987,J. Viral. 61, 2807-2815). To characterize the mechanism of trans-activation by the tar, we used gel shift assays to demonstrate that there exist proteins in virus-infected cellular extracts which have higher binding activity than that found in mock-infected extracts. These observations in vitro are consistent with the expression by P38 constructs with the wild-type promoter linked to a reporter gene, chloramphenicol acetyl transferase (cat), in viva. We also provide evidence that the protein(s)-tar complex has a molecular mass of approximately 75 kDa in an SDS-polyacrylamide gel, which is less than NSl, and this complex cannot be precipitated by NSl antibody, which suggests that NSl mediates the trans-activation by inducing an alteration in the binding activity of some cellular protein(s) in an indirect manner. These data support our previous hypothesis for the activation of the P38 promoter, in which the trans-activator(s) interacts with the tar effectively in the presence of NSl, leading to the formation of the transcription initiation complex by protein-protein associations (Gu, Chen, and Rhode, 1992, Virology 187, 1 O-l 7).

Research paper thumbnail of Ultrastructural Studies of H-1 Parvovirus Replication VI. Simultaneous Autoradiographic and Immunochemical Intranuclear Localization of Viral DNA Synthesis and Protein Accumulation

Journal of Virology, 1978

Research paper thumbnail of The Effect of Coumermycin A1on the Meningococcal Carrier State

The American Journal of the Medical Sciences, Sep 1, 1970

Research paper thumbnail of Replication process of the parvovirus H-1. IX. Physical mapping studies of the H-1 genome

Journal of Virology, May 1, 1977

Research paper thumbnail of Replication Process of the Parvovirus H-1 II. Isolation and Characterization of H-1 Replicative Form DNA

Journal of Virology, Feb 1, 1974

Research paper thumbnail of Evaluation of Group C Meningococcal Polysaccharide Vaccine in Marine Recruits, San Diego, CALIFORNIA1

American Journal of Epidemiology, Jul 1, 1970

Group C meningococcal polysaccharide vaccine was well tolerated by 3,018 vaccinated Marine recrui... more Group C meningococcal polysaccharide vaccine was well tolerated by 3,018 vaccinated Marine recruits. The vaccine appeared to be groupspecific since it prevented the acquisition of only group C meningococci. The vaccine stimulated a good hemagglutinating antibody response, but did not stimulate a comiplement fixing antibody response. One systemic illness of uncertain etiology, possibly vaccine related, vw observed among the vaccinees. That the vaccine affords protect ion against clinical disease was suggested when three cases of meningococcal disease of group C etiology developed in the nonvaccinated controls thile none occurred among the vaccinated men of the study population. Reproduced by NATIONAL TECHNICAL INFORMATION SERVICE U S Departm~ent of Conmmerce Springfied VA 22151 DD14 34 UNCLASSIPIED Seernity Clsfle"maoe Reproduced by permission of The Williams & Wilkins Company. Further reproduction prohibited.

Research paper thumbnail of Replication process of the parvovirus H-1 V. Isolation and characterization of temperature-sensitive H-1 mutants

Journal of Virology, Feb 1, 1976

Two temperature-sensitive mutants of the parvovirus H-1 have been isolated and characterized. The... more Two temperature-sensitive mutants of the parvovirus H-1 have been isolated and characterized. These mutants are distinguishable by the immunofluorescent

Research paper thumbnail of Ultrastructural studies of H-1 parvovirus replication. V. Immunocytochemical demonstration of separate chromatin-associated and inclusion-associated antigens

Journal of Virology, Oct 1, 1977

Electron microscopy and immunocytochrome c staining were used to define the phenotypes of several... more Electron microscopy and immunocytochrome c staining were used to define the phenotypes of several temperature-sensitive (ts) H-1 mutants. They were classified into three separate groups based on the properties of their capsids at the restrictive temperature (rT): (class 1) ts2 did not assemble capsids but produced spherical and irregular amorphous inclusions; (class 2) tsl and ts7 exclusively synthesized empty particles which all aggregated and crystallized; and (class 3) ts8 and ts1O formed noncrystalline aggregates of empty virions, but many individual full, as well as empty, capsids were associated with euchromatin. Synthesis of progeny DNA and hemagglutinin at rT were normal for class 3 mutants, but defective for those in classes 1 and 2. The immunospecific staining patterns of these mutants indicated that the H-1 capsid proteins probably form two separate intranuclear antigens: (i) a thermostable chromatin-associated antigen present in proteins that have not formed capsids and are concentrated on heterochromatin and nucleolar-associated chromatin and (ii) a thermolabile inclusion-associated antigen found in the proteins of assembled empty capsids that compose H-1 inclusions. H-1 is a small (25 nm) icosahedral parvovirus (3) requiring the late Sor G2-phase of the host cell cycle for replication (7). Its single-stranded DNA has a molecular weight of about 1.6 x 106 (15) and codes for only two viral capsid polypeptides (VP1 and VP2') in vivo (4). Very similar capsid components are present in the parvovirus minute virus of mice (18), and it appears that the amino acid sequence of VP2' is contained within VP1, the larger polypeptide (19). Studies on parvovirus transcriptional capacities show that a single mRNA capable of coding for only VP1 is made by adenovirus-associated virus (2) and by Kilham rat virus (10). Also, many different temperature-sensitive (ts) mutants of H-1 have been isolated in our laboratory, and the six that have been tested failed to show complementation, implying that the mu

Research paper thumbnail of Ultrastructural studies of H-1 parvovirus replication. IV. Crystal development and structure with the temperature-sensitive mutant ts1

Journal of Virology, Oct 1, 1977

Electron microscopy was used to study the development and structure of viral crystals of ts 1, a ... more Electron microscopy was used to study the development and structure of viral crystals of ts 1, a temperature-sensitive mutant of H-1 parvovirus. At early times postinfection, at the restrictive temperature, empty H-1 capsids aggregated to form conspicuous noncrystalline conglomerates in human NB cell nuclei; these particles did not associate with euchromatin as in wild-type H-1 infections. Later on, the capsid aggregates appeared to form polycrystals exhibiting rodlike, hexagonal, and cubic patterns that were interconvertible using a goniometer specimen stage. The unit cell of this crystal was cubic, consisted of 16 empty particles, and measured 50 nm on each side. Full particles made at the permissive temperature were never observed under restrictive conditions. Experiments in which cultures were shifted from the permissive to the restrictive temperature showed that full virions were not incorporated into crystals. The crystals dissociated into individual particles when changes were made from restrictive to permissive conditions. Correlations between the formation of crystals at the restrictive temperature, their dissociation into capsid components after shifting from the restrictive to the permissive state, and the extent of host cell damage were also observed. Possible roles of cellular functions in regulating tsl H-1 polycrystal assembly and dissociation are discussed.