Cancer Res Treat.  2011 Dec;43(4):250-254.

Expression of BamHI-A Rightward Transcripts in Epstein-Barr Virus-Associated Gastric Cancers

• Jang BG
• Jung EJ
• Kim WH

Abstract

PURPOSE
About 10% of all gastric cancers (GCs) are Epstein-Barr virus (EBV)-associated. However, the oncogene of EBV in gastric carcinogenesis has not yet been established. In the present study, we investigated the virus-derived transcripts in the EBV-infected GC cell line to explore the viral oncogene of EBV-positive GCs.
MATERIALS AND METHODS
We used the SNU719 cell line, a naturally derived EBV-infected GC cell line. The individual expressed sequence tags from the cDNA libraries of SNU719 were searched against the mRNA subset extracted from the GenBank data base. Sequence reaction was carried out for the EBV-associated clones. Reverse transcription-polymerase chain reaction was performed after cells were partitioned into nuclear and cytoplasmic fractions.
RESULTS
Using bioinformatic tools, we selected 13 EBV-associated clones from cDNA libraries of SNU719. By sequencing analysis, we revealed that they were all associated with RPMS1, one of the BamHI-A rightward transcripts (BART) of EBV. Some BART cDNAs such as RPMS1 and A73 are known to be translated into protein in vitro, and have been shown to have some biochemical functions relevant to tumorigenesis. But, presently, the BART transcripts were expressed only in the nucleus and not in the cytoplasm, arguing against their role as messenger RNAs. Some other BART transcripts expressed in GCs (BARF0, CST, vIL, BARF1, BLLF1, and BcLF1) were also extensively detected in the nucleus.
CONCLUSION
BART transcripts are the predominant viral transcripts expressed in EBV-associated GCs, and they are located only in the nucleus. Therefore, it seems less likely that BART transcripts produce functional proteins to play a role in carcinogenesis of EBV-associated GCs.

Keyword

Stomach neoplasms; Epstein-Barr virus; Oncogenes; RPMS protein

MeSH Terms

Cell Line
Cell Transformation, Neoplastic
Clone Cells
Cytoplasm
Databases, Nucleic Acid
DNA, Complementary
Expressed Sequence Tags
Gene Library
Herpesvirus 4, Human
Oncogenes
Proteins
RNA, Messenger
Stomach Neoplasms
DNA, Complementary
Proteins
RNA, Messenger

Figure

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  Fig. 1 Electrophoresis of 13 clones after digestion with EcoR I and Not I. Clones 1, 2, 4, 6, 10, 11 and 13 showed two fragments of 1.2 kb and 0.4 kb because of their EcoR I recognition sites.

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  Fig. 2 Sequence alignment of three groups of clones to the RPMS1 cDNA. The BLAST sequence alignment program was used to compare the sequence of the clones to RPMS1. The open reading frames (ORFs) of RPMS1 and A73 are shown by boxed segments.

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  Fig. 3 Analysis of Epstein-Barr virus (EBV) transcripts comparing cytoplasmic and nuclear RNA from SNU719. (A) Reverse transcriptase polymerase chain reaction (RT-PCR) for BamHI-A rightward transcripts (BART) RNAs using primers spanning BART exons 3B-5 or 5-7. (B) RT-PCR for the some latent and lytic EBV transcripts. The glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene was used as an internal control.

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