RESUMO
The complete ORF54 of the Kaposi's sarcoma-associated herpesvirus (KSHV) (human herpesvirus-8; HHV-8) was cloned and expressed in E. coli. The results show that KSHV/HHV-8 ORF54 encodes a functional dUTPase which specifically hydrolyses dUTP to dUMP. Monoclonal antibodies against the HHV-8 dUTPase detected a protein with the expected molecular mass of 35 kDa in HHV-8-infected BCBL-1 cells. Induction of the lytic replication cycle of HHV-8 by treatment of BCBL-1 cells with the phorbol ester TPA resulted in an increased expression of the protein which was not inhibited by phosphonoacetic acid, indicating that the protein is expressed early in the lytic replication cycle. Moreover, the sporadic expression of the HHV-8 dUTPase in tissue sections of Kaposi's sarcoma was detected by immunohistochemistry.
Assuntos
Herpesvirus Humano 8/enzimologia , Fases de Leitura Aberta/genética , Pirofosfatases/genética , Pirofosfatases/metabolismo , Replicação Viral , Genes Virais , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/fisiologia , Humanos , Imuno-Histoquímica , Hibridização In SituRESUMO
The present investigation was carried out to estimate the prevalence of EBV-associated cases among gastric carcinoma (GC) patients of Russia and the Republics of the former Soviet Union (FSU). With this aim, formalin-fixed paraffin-embedded blocks from 206 gastric carcinomas obtained from patients of the Cancer Research Center, Moscow, were investigated by EBV-encoded RNA-1 (EBER-1) in situ hybridization applied to paraffin sections. As a result, 18 GC cases (8.7%) revealed uniform EBER-1 expression restricted to the carcinoma cells. Hybridized signals not detected in non-neoplastic gastric epithelium. EBV involvement was significantly more frequent among males, especially in tumors of less differentiated types (moderately differentiated tubular adenocarcinomas and poorly differentiated solid adenocarcinomas) and located in the upper stomach (cardia and middle). Most EBV-positive GCs were characterized by strong lymphoid-compartment involvement. Our findings concerning the distribution of EBV-positive GCs by sex, site and hystological type are similar to those in Japan, however, EBV-positive rate of GC cases in Russia is higher than in Japan and lower than in USA.
Assuntos
Adenocarcinoma/epidemiologia , Adenocarcinoma/virologia , Infecções por Herpesviridae/complicações , Herpesvirus Humano 4/isolamento & purificação , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/virologia , Adenocarcinoma/complicações , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Feminino , Humanos , Hibridização In Situ , Masculino , Pessoa de Meia-Idade , RNA Viral/análise , Federação Russa/epidemiologia , Distribuição por Sexo , Neoplasias Gástricas/complicações , Neoplasias Gástricas/patologia , Infecções Tumorais por Vírus/complicaçõesRESUMO
Previously we demonstrated differences in the organization and methylation pattern of integrated Rous sarcoma proviral sequences in helper-dependent virogenic rat TWERC cells. In the present study we attempted to induce changes in the integrated viral genome of TWERC cells using 5-bromodeoxyuridine (BrdU). Four clones (A, B, C, and F) derived from the parental cell line were treated for 10 months with different concentrations of BrdU. Restriction enzyme analysis of the parental cell line and its clones showed that the cells contained in their genomic DNA two copies of deleted provirus. In TWERC cells, the PR-RSV provirus lost the whole env gene and part of the 3' end of the pol gene. The proviral sequences in DNA from the TWERC-derived clones were found to be hypermethylated. A slightly different situation was seen in clone C where demethylation of the provirus in the 3' region and in the 5' end of the genome was found. The level of mRNA expression both in the parental cells and in the clones correlated with the methylation pattern of the PR-RSV provirus. Clone C was less methylated and expressed more virus-specific RNA. The possible role of BrdU in these events is discussed.