Cooperativity among herpes simplex virus type 1 immediate-early regulatory proteins: ICP4 and ICP27 affect the intracellular localization of ICP0

The results of transient expression assays and studies of viral mutants have shown that three of the five immediate-early proteins of herpes simplex virus type 1 (HSV-1) perform regulatory functions, individually and cooperatively. As part of efforts designed to explore the molecular basis for the functional cooperativity among ICP0, ICP4, and ICP27 in the regulation of HSV gene expression, we have examined the intracellular localization of ICP0 in cells infected with ICP4 and ICP27 null mutant viruses by indirect immunofluorescence. Although ICP0 was localized predominantly to the nuclei of wild-type virus-infected cells, it was found exclusively in the nuclei of ICP27 mutant-infected cells and in both the cytoplasm and nuclei of ICP4 mutant-infected cells, the cytoplasmic component being especially strong. These observations indicate that both ICP4 and ICP27 can affect the intracellular localization of ICP0. Transient expression assays with plasmids that express wild-type and mutant forms of ICP0, ICP4, and ICP27 confirmed that ICP4 promotes and that ICP27 inhibits the nuclear localization of ICP0. These results confirm the observations made for mutant virus-infected cells and indicate that the localization pattern seen in infected cells can be established by these three immediate-early proteins exclusive of other viral proteins. The C-terminal half of ICP27 was shown to be required to achieve its inhibitory effect on the nuclear localization of ICP0. The region of ICP0 responsive to ICP27 was mapped to the C terminus of the molecule between amino acid residues 720 and 769. In addition, the concentration of ICP27 was shown to have a significant effect on the intracellular localization of ICP0. Because the major regulatory activities of ICP0, ICP4, and ICP27 are expressed in the nucleus, the ability of these three proteins collectively to determine their own localization patterns within cells adds a new dimension to the complex process of viral gene regulation in HSV.

The measurement of DNA content in Wilms' tumor and its clinical significance

DNA content analysis with paraffin-embedded tissue was performed by flow cytometry on extracted nuclei from 42 Wilms' tumors. DNA histograms showed diploid in 13, tetraploid in 12, and aneuploid in 17. The frequency of DNA aneuploid was 40.48%. The 2- and 5-year survival rates were 84% and 75.16%, respectively, for patients with the DNA diploid pattern; the 2- and 5-year DNA aneuploid survival rates were 47.06% and 41.18% (P < .03 and P < .05), respectively. The 2- and 5-year survival rates for DNA tetraploid were in between, both 55.90%. For patients with stage I and II, the difference in the 2- and 5-year survival rates between DNA diploid plus tetraploid and DNA aneuploid was even more significant (P < .004 and P < .002, respectively). Thus, DNA aneuploid is an important indicator of poor prognosis in Wilms' tumor, especially for stages I and II.

The herpes simplex virus type 1 regulatory protein ICP0 enhances virus replication during acute infection and reactivation from latency

ICP0 is a potent activator of herpes simplex virus type 1 gene expression in transient assays and in productive infection. A role for ICP0 in reactivation from latency in vivo has also been suggested on the basis of the observation that viruses with mutations in both copies of the diploid gene for ICP0 reactivate less efficiently than wild-type virus. Because the ICP0 gene is contained entirely within the coding sequences for the latency-associated transcripts (LATs), ICP0 mutants also contain mutations in LAT coding sequences. This overlap raises the question of whether mutations in ICP0 or the LATs, which have also been implicated in reactivation, are responsible for the reduced reactivation frequencies characteristic of ICP0 mutants. Two approaches were taken to examine more definitively the role of ICP0 in the establishment and reactivation of latency. First, a series of ICP0 nonsense, insertion, and deletion mutant viruses that exhibit graded levels of ICP0-specific transactivating activity were tested for parameters of the establishment and reactivation of latency in a mouse ocular model. Although these mutants are ICP0 LAT double mutants, all nonsense mutants induced the synthesis of near-wild-type levels of the 2-kb LAT, demonstrating that the nonsense linker did not disrupt the synthesis of this LAT species. All mutants replicated less efficiently than the wild-type virus in mouse eyes and ganglia during the acute phase of infection. The replication efficiencies of the mutants at these sites corresponded well with the ICP0 transactivating activities of individual mutant peptides in transient expression assays. All mutants exhibited reduced reactivation frequencies relative to those of wild-type virus, and reactivation frequencies, like replication efficiencies in eyes and ganglia, correlated well with the level of ICP0 transactivating activity exhibited by individual mutant peptides. The amount of DNA of the different mutants varied in latently infected ganglia, as demonstrated by polymerase chain reaction analysis. No correlation was evident between reactivation frequencies and the levels of viral DNA in latently infected ganglia. Thus, replication and reactivation efficiencies of ICP0 mutant viruses correlated well with the transactivating efficiency of the corresponding mutant peptides. In a second approach to examining the role of ICP0 in latency, a single copy of the wild-type gene for ICP0 was inserted into the genome of an ICP0- LAT- double mutant, 7134, which exhibits a marked impairment in its ability to replicate in the mouse eye and reactivate from latency.(ABSTRACT TRUNCATED AT 400 WORDS)

Herpes simplex virus (HSV) glycoproteins B and K inhibit cell fusion induced by HSV syncytial mutants

Herpes simplex virus type 1 (HSV-1) glycoproteins K and B (gK and gB) are intimately involved in virus-induced fusion of cells. Certain mutations in the UL27 (gB) and UL53 (gK) genes confer a syncytial (syn) phenotype characterized by extensive fusion of infected cells and giving rise to multinucleated cells. We have used HSV-1 syn mutants in conjunction with transfected cells or adenovirus vectors to overexpress wild-type gK or gB, in order to study the role of these proteins in virus-induced membrane fusion. Transient expression of wild-type gK inhibited fusion induced by HSV-1 encoding a mutant form of gK (syn gK) but not by viruses encoding a mutant form of gB (syn gB). Stably transformed cells expressing relatively high levels of gK suppressed cell fusion induced by HSV-1 mutants with lesions in the gK gene but not an HSV-1 with a syn mutation in the gB gene. In addition, there were marked reductions in the plaquing efficiencies and yields of HSV-1 on these cell lines. Cell fusion caused by HSV-1 syn20, a mutant encoding syn gK, was suppressed when cells were coinfected with an Ad vector, AdgK, which expresses wild-type gK. AdgK did not suppress fusion induced by HSV-1 KTTS.1, which expresses syn gB. Conversely, cells coinfected with AdgB, an Ad vector expressing a wild-type form of gB and HSV-1 KTTS.1 (syn gB) were not fused, whereas cells coinfected with AdgB and HSV-1 syn20 (syn gK) were fused. Expression of a number of other HSV-1 glycoproteins using Ad vectors did not reduce membrane fusion induced by syn gK or syn gB. Together, these results support models in which gK and gB participate directly in the fusion of HSV-infected cells. Mutant forms of gB and gK apparently disregulate the fusion process, whereas wild-type forms of gB and gK can act to suppress membrane fusion induced by their mutant counterparts.

Influence of medicinal herbs on phagocytosis by bovine neutrophils

Twenty-six herbal preparations made from 24 medicinal herbs, categorized as antipyretics in Chinese materia medica, were tested in vitro to determine their effects upon phagocytosis of 32P-labelled Staphylococcus aureus by neutrophils isolated from bovine blood and milk. The percentage of phagocytosis was determined after incubating (1 hour at 37 degrees C) 1.25 x 10(7) neutrophils, 1 x 10(8) 32P-labelled S. aureus and 10% skimmed milk with herbal solutions. Concentrations of herbal preparations tested were 100%, 10% and 1% (v/v). When compared with PBSS (0.01 M phosphate buffered saline solution) controls, most of the herbs at high concentrations inhibited phagocytosis while at lower concentrations phagocytosis was increased. All 26 herbal preparations significantly increased blood neutrophil activity at their proper concentrations. The most active herbs in promoting blood neutrophil phagocytosis were observed for Herba verbenae, Flos chrysanthemi, Flos lonicerae, Radix sophorae flavescentis, Herba houttuyniae, Radix isatidis, Herba patriniae, Berberini sulfatis at the lowest concentration and for Folium hibisci at the high concentration with the increased percentage of more than 40.0% in comparison with PBSS control. Of the 19 herbal preparations tested with milk neutrophils, 18 herbs greatly increased phagocytosis at suitable concentrations. The most active preparations in stimulating milk neutrophil functions included Folium hibisci, Flos chrysanthemi, Radix bupleuri, Radix stellariae, Herba houttuyniae, Herba senecionis scandentis, Caulis lonicerae and Flos lonicerae which increased phagocytosis by over 35.0%.

Herpes simplex virus type 1 ICP0 regulates expression of immediate-early, early, and late genes in productively infected cells

The herpes simplex virus type 1 protein, ICP0, can activate expression of all kinetic classes of viral promoters in transient expression assays. To examine the role of ICP0 in the regulation of viral gene expression during productive infection, we characterized the wild-type virus, an ICP0 null mutant (7134), and several ICP0 nonsense mutant viruses with regard to virus replication and protein synthesis in Vero cells. Relative to wild-type virus, 7134 was severely deficient in viral growth and protein synthesis at low multiplicities of infection but exhibited a nearly wild-type phenotype at high multiplicities. The phenotypes of the ICP0 nonsense mutants were intermediate between those of the wild-type virus and 7134 in that the more ICP0-coding sequence expressed by a given nonsense mutant, the more wild type-like was its phenotype. The location of the ICP0 domain responsible for transactivation during productive infection was confirmed to be within the N-terminal portion of the protein, as previously shown in transient expression assays. Immunoprecipitation and immunofluorescence tests were used to detect low-level expression of selected immediate-early (IE), early (E), and late (L) proteins by mutant and wild-type viruses following low-multiplicity infection. The 7134 deletion mutant and several nonsense mutants expressed markedly reduced levels of E and L proteins but wild-type levels of the IE protein, ICP4. Because the latency-associated transcripts (LATs) are specified by the strand opposite that which encodes ICP0, the ICP0 deletion and nonsense mutants are by definition ICP0-LAT double mutants. The ability of a LAT- ICP0+ mutant to replicate as efficiently as wild-type virus at low multiplicities and the ability of ICP0-expressing 0-28 cells to complement the defects of the mutants in E and L protein synthesis indicates that the phenotypes of the mutants are caused by mutations in ICP0 and not the LATs. Thus, we conclude that ICP0 up-regulates E and L but not necessarily IE gene expression during productive infection. The activation of IE gene expression by ICP0 during productive infection is likely overshadowed by the activity of the virion-associated protein, VP16. This hypothesis was tested by transfection of Vero cells with infectious mutant and wild-type viral DNAs. In such tests, no VP16 is present at early times posttransfection. Significantly fewer cells transfected with infectious 7134 DNA expressed ICP4 than cells transfected with KOS DNA. This reduction was fully reversed by cotransfection with an ICP0-expressing plasmid.(ABSTRACT TRUNCATED AT 400 WORDS)

Acupuncture and the nervous system

Acupuncture is based on neuroanatomy and neurophysiology. At each acupuncture point, there are peripheral nerves and terminals. Acupuncture will be useful for further understanding of the nervous system. A conceptual view of acupuncture's physiology is presented.

A cellular function can enhance gene expression and plating efficiency of a mutant defective in the gene for ICP0, a transactivating protein of herpes simplex virus type 1

ICP0 transactivates herpes simplex virus type 1 genes of all classes as well as a number of heterologous viral and cellular genes, yet it is not essential for virus replication in vitro or in vivo. Stocks of ICP0 deletion mutants, however, exhibit significantly lower plating efficiencies on standard 24-h-old Vero cell monolayers than do stocks of wild-type virus. In an attempt to determine whether the growth status of cells in the monolayer affects the ability of ICP0 mutants to initiate plaque formation, the plating efficiencies and abilities of an ICP0 null mutant (7134) and of wild-type virus (KOS) to express selected viral proteins were determined on Vero cell monolayers whose growth had been arrested either by contact inhibition-trypsinization or by isoleucine deprivation and had then been released from growth arrest. The proportion of cells cycling synchronously after release from growth arrest was assessed by flow cytometry. The results of these studies indicate that the plating efficiency of 7134 was greatest on Vero cell monolayers 8 h after release from growth arrest induced by either treatment. Monolayers of both types released from growth arrest at other times supported 7134 plaque formation less efficiently. In contrast, the plating efficiency of KOS was nearly equal on monolayers at all times after release from growth arrest. Notably, both KOS and 7134 were equally efficient in entering cells and inducing expression of the immediate-early protein ICP4 in either 8- or 24-h monolayers. Relative to KOS, however, 7134 was significantly impaired in the expression of selected early and late genes in cells at 24 h postrelease. When the plating efficiencies of 7134 and KOS were examined in 0-28 cells (Vero cells that are stably transformed with the ICP0 gene) whose growth had been arrested and then released, no differences in the plating efficiencies of the two viruses as a function of growth status were noted. These findings suggest that a cellular function expressed maximally in cells 8 h after release from growth arrest can substitute operationally for ICP0 to enhance plaque formation and viral gene expression by 7134. They further suggest that one role of ICP0 in viral infection is to facilitate virus replication in cells that do not express this function.

[Changes in plasma TXB2 and 6-keto-PGF1 alpha and left atrial thrombosis in mitral stenosis]

This study was performed to determine the relationship between plasma concentration of thromboxane B2 (TXB2), 6-keto-prostaglandin F1a and atrial thrombosis in patients with mitral stenosis (MS). By radioimmunoassay and pathological examination, peripheral plasma TXB2 level was remarkably higher in patients with MS and persistent atrial fibrillation (AF) than in patients with MS but without AF (P less than 0.01). Plasma TXB2 level was significantly higher in patients with than in those without atrial thrombosis (P less than 0.05). There was no significant difference in plasma 6-keto-PGF1 alpha, plasma prostanoids level in peripheral venous blood correlated closely with that in left atrial blood. Patients with high plasma TXB2 level had a greater incidence of microthrombosis.

Identification of mar mutations in herpes simplex virus type 1 glycoprotein B which alter antigenic structure and function in virus penetration

Analysis of six monoclonal antibody-resistant (mar) mutants in herpes simplex virus type 1 glycoprotein B identified two type-common (II and III) and two type-specific (I and IV) antigenic sites on this molecule. To derive additional information on the location of these sites, mar mutations were mapped and nucleotide alterations were identified by DNA sequencing. Each mutant carried a single amino acid substitution resulting from a G-to-A base transition. Alterations affecting antibody neutralization were identified at residues 473, 594, 305, and 85 for mutants in sites I through IV, respectively. Two clonally distinct site II antibodies each selected mar mutants (Gly to Arg at residue 594) that exhibited a reduction in the rate of entry (roe) into host cells. A site II mar revertant that regained sensitivity to neutralization by site II antibodies also showed normal entry kinetics. DNA sequencing of this virus identified a single base reversion of the site II mar mutation, resulting in restoration of the wild-type sequence (Arg to Gly). This finding demonstrated that the mar and roe phenotypes were the result of a single mutation. To further define structures that contributed to antibody recognition, monoclonal antibodies specific for all four sites were tested for their ability to immune precipitate a panel of linker-insertion mutant glycoprotein B molecules. Individual polypeptides that contained single insertions of 2 to 28 amino acids throughout the external domain were not recognized or were recognized poorly by antibodies specific for sites II and III, whereas no insertion affected antibody recognition of sites I and IV. mar mutations affecting either site II or III were previously shown to cause temperature-sensitive defects in glycoprotein B glycosylation, and variants altered in both these sites were temperature sensitive for virus production. Taken together, the data indicate that antigenic sites II and III are composed of higher-order structures whose integrity is linked with the ability of glycoprotein B to function in virus infectivity.

The carboxy-terminal 41 amino acids of herpes simplex virus type 1 glycoprotein B are not essential for production of infectious virus particles

Glycoprotein B (gB) is a virally encoded protein that is found in the envelope of herpes simplex virus type 1 and membranes of cells infected with herpes simplex virus type 1. It is essential for the production of infectious virus particles. An amber mutation was introduced into the gB gene by oligonucleotide-directed mutagenesis at the codon for amino acid 863 of the protein. Virus carrying this mutation should synthesize gB molecules lacking the last 41 amino acids of the cytoplasmic domain. Immunoprecipitation of infected cell extracts demonstrated the synthesis of appropriately truncated gB molecules. Characterization of the mutant virus indicated that the loss of the carboxy-terminal 41 amino acids has little effect on gB function.