摘要:

Fusion of Epstein-Barr virus (EBV) with Raji cells was measured after exposure of the virus to neutral or low pH, enzymatic modification of the viral spike glycoproteins, or chemical modification of the target membrane. The relief of octadecylrhodamine (R18) fluorescence self-quenching was used to monitor fusion. Fusion of EBV with Raji cells at pH 5.9 was significantly enhanced compared to that at neutral pH. Treatment of Raji cells with agents known to modify the surface net charge (trinitrobenzene sulfonic acid) totally prevented fusion at a neutral pH. Desialylation of EBV significantly reduced the extent of fusion with Raji cells. Our results demonstrate that EBV is rapidly internalized and then fuses with lymphoblastoid cells in the endocytic vesicles.

ISSN:0300-5526    

DOI:10.1159/000150248

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The nucleotide sequence of Epstein-Barr virus (EBV) nuclear antigen (EBNA)-2 and EBNA-3B regions of an EBV-2 isolate in Japan was analyzed. The deduced amino acid sequences of EBNA-2 and EBNA-3B of the isolate and a prototype EBV-2 strain AG876 were identical, but the number of the repeated sequence in EBNA-3B was variable as that of IR-3 in EBNA-1. The remarkably well-conserved sequence seems to suggest that the structure of the EBNA-2 and EBNA-3B genes of EBV-2 is crucial for their function in virus replication.

ISSN:0300-5526    

DOI:10.1159/000150249

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Human cervical and NIH 3T3 cells were transfected with the XbaI-E-transforming fragment of human cytomegalovirus strain Towne. Southern blot hybridization showed that 3 of 4 transformed NIH 3T3 cell lines retained only the mtrII subfragment of Towne Xbal-E, but not the mtrlll subfragment. Even though mtrII was retained, no viral transcripts were detected. Analysis of genomic DNAs isolated from three independently derived lines of Towne XbaI-E-transfected human exocervical epithelial cells previously immortalized by human papillomavirus type 16 (CX16-2/Towne-E) revealed the retention of both mtrll and mtrlll subfragments of Towne Xba 30 subpassages. Southern blot hybridizations indicated the integration and rearrangement of mtrll as well as mtrlll. Poly (A)+RNA analysis of a CX16-2/Towne-E line revealed a 1.9-kb transcript which hybridized to mtr III. In contrast, no viral transcript from the mtrll region was detected in these cells. The pattern of HPV-16 DNA sequences and the profile of RNA transcripts were similar in the parental human exocervical cells (CX16-2) and in the CX16-2/Towne-E cells. Thus far, the CX16-2/Towne-E lines are nontumorigenic in nude mice. This study highlights not only differences in the ability of Towne Xbal-E to transform rodent cells and not human cells but also differences in the retention and expression of mtrll and mtrlll in these cells.

ISSN:0300-5526    

DOI:10.1159/000150250

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

DsRNA has been extracted from beet pseudo-yellows virus infected cucumber plants, purified to homogeneity, and cDNA clones to it produced. The clones are of insufficient sensitivity to detect infection-specific RNA in dot and northern blots of crude nucleic acid extracts. However, a knowledge of the sequence of these clones has been used to synthesize oligonucleotides that have been used for polymerase chain reaction amplification of specific sequences from both purified dsRNA and from infected plants and used as a previously unavailable highly sensitive diagnostic probe. The method of cDNA synthesis has been shown to be generally applicable to some other plant viral dsRNAs and should be of use in the production of cDNA clones when virion RNA is unavailable.

ISSN:0300-5526    

DOI:10.1159/000150251

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Guinea pigs were infected with herpes simplex virus (HSV) intravaginally and then sacrificed during latent infection. Virus was recovered from the ganglia, spinal cord and genital tissues by co-cultivation after 1-6 weeks in culture. The virus could not be recovered from the genital tract during the first week of co-cultivation, nor from homogenized genital tissue. Cultivation of genital tissues with acyclovir did not reduce the recovery of HSV. Thus, HSV appeared to establish a truly latent infection in the genital tract and not a persistent infection as previously described.

ISSN:0300-5526    

DOI:10.1159/000150252

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

We have further analyzed structure and expression of the E1 region of the transformation-defective adenovirus 12 (Ad12) host range mutant CS-1. Using cDNA polymerase chain reaction analysis, the E1a region was found to give raise to five transcripts analogous to the Ad12wt 13S, 12S, US, 10S species and the normal 9S mRNA. Due to loss of a splice acceptor site at position 852, the Ad12wt-specific 9.5S transcript cannot be synthesized by the mutant CS-1. The fact that the virus is, however, completely viable indicates that this mRNA is dispensable for lytic growth of Ad12. Besides the deletions in E1a described previously, a second deletion of 31 base pairs was found in the E1b gene. It affects the start site of the E1b-specific mRNAs and destroys or eliminates the AUG sequence for the E1b 19-kD protein. As shown earlier, normal E1b mRNA expression is found in mutant-infected cells, but no 19-kD E1b protein was immunoprecipitated by an E1-specific rat tumor serum.

ISSN:0300-5526    

DOI:10.1159/000150253

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

12-0-Tetradecanoyl phorbol-13-acetate (TPA) has been widely known as an activator of Epstein-Barr Virus (EBV) replication and is a direct activator of protein kinase C (PKC). These facts suggest that EBV DNA synthesis might at least partly be dependent upon PKC activity. In this report, the effects of two different types of PKC inhibitors on EBV DNA synthesis were investigated by slot blot hybridization using a biotin-labeled probe. Staurosporine and H-7, inhibitors acting on the catalytic domain of PKC, prevented the growth reduction of P3HR-1 cells harboring EBV genomes and the induction of viral DNA synthesis by TPA. Calphostin C and sphingosine, which have been reported to suppress the enzyme activity by acting on the regulatory domain of PKC, did not exert efficiently effects on cellular growth and viral replication at increasing concentrations of TPA. From these results it is suggested that PKC is involved in the control of viral DNA synthesis in P3HR-1 cells and that for the inhibition of virus growth, it is more efffective to suppress the activity of the catalytic domain of this enzyme than acting on the regulatory domain and competing with PKC activators such as TPA for binding.

ISSN:0300-5526    

DOI:10.1159/000150254

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150255

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150256

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150247

出版商:S. Karger AG    

年代:1992

数据来源: Karger