Transcriptional activation by EBV nuclear antigen 1 is essential for the expression of EBV's transforming genes.
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ABSTRACT:
SUBMITTER: Altmann M
PROVIDER: S-EPMC1599932 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:[This corrects the article DOI: 10.1371/journal.ppat.1006890.].
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Project description:The Epstein-Barr virus (EBV) is a ubiquitous B-lymphotropic herpesvirus associated with several malignant tumors, e.g., Burkitt's lymphoma and Hodgkin's disease, and is able to efficiently immortalize primary B lymphocytes in vitro. The growth program of infected B cells is initiated and maintained by the viral transcription factor EBV nuclear antigen 2 (EBNA2), which regulates viral and cellular genes, including the proto-oncogene c-myc. In our study, patterns of protein expression in B cells with and without EBNA2 were analyzed by two-dimensional polyacrylamide gel electrophoresis and mass spectrometry. For this purpose, we used a conditional immortalization system for EBV, a B cell line (EREB2-5) that expresses an estrogen receptor-EBNA2 fusion protein. In order to discriminate downstream targets of c-Myc from c-Myc-independent EBNA2 targets, we used an EREB2-5-derived cell line, P493-6, in which c-Myc is expressed under the control of a tetracycline-regulated promoter. Of 20 identified EBNA2 target proteins, 11 were c-Myc dependent and therefore most probably associated with proliferation, and one of these proteins was a posttranslationally modified protein, i.e., hypusinylated eIF5a. Finally, to estimate the relevance of EBNA2 targets during early EBV infection, we analyzed the proteomes of primary B cells before and after infection with EBV. The protein expression pattern induced upon EBV infection was similar to that following EBNA2 activation. These findings underscore the value of EREB2-5 cells as an appropriate model system for the analysis of early events in the process of EBV-mediated B-cell immortalization.
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Project description:The WHO has recently classified Neisseria gonorrhoeae as a super-bacterium due to the rapid spread of antibiotic resistant derivatives and an overall dramatic increase in infection incidences. Genome sequencing has identified potential genes, however, little is known about the transcriptional organization and the presence of non-coding RNAs in gonococci. We performed RNA sequencing to define the transcriptome and the transcriptional start sites of all gonococcal genes and operons. Numerous new transcripts including 253 potentially non-coding RNAs transcribed from intergenic regions or antisense to coding genes were identified. Strikingly, strong antisense transcription was detected for the phase-variable opa genes coding for a family of adhesins and invasins in pathogenic Neisseria, that may have regulatory functions. Based on the defined transcriptional start sites, promoter motifs were identified. We further generated and sequenced a high density Tn5 transposon library to predict a core of 827 gonococcal essential genes, 133 of which have no known function. Our combined RNA-Seq and Tn-Seq approach establishes a detailed map of gonococcal genes and defines the first core set of essential gonococcal genes.
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