Differential expression and localization of EBER-1 and EBER-2 in Epstein-Barr virus-carrying cells.

Abstract

Objective: The functions of the Epstein-Barr virus (EBV)-encoded small RNAs (EBER-1 and EBER-2) are unknown. We examined their fine intranuclear localization as the first step to investigate their function.

Methods: We analyzed EBER-1 and EBER-2 by in situ hybridization combined with two-color immunofluorescence tagging.

Results: EBER-1 was visualized as fine dots, mainly in the euchromatin. Ribosomal protein L-22 also formed fine dots, similar to those formed by EBER-1, in the nuclei of EBV-carrying cells and colocalized with the latter by double staining. EBER-2 was predominantly found in the nucleoli and was also present in the euchromatin. The two EBERs were similarly expressed in B-cell lines of the different phenotypes examined. The EBERs showed no colocalization by double staining. Image analysis indicated that the level of their expression was not correlated.

Conclusion: The differential localization and expression of the EBER-1 and EBER-2 suggests that they may play different functional roles.