HEPATITIS-D VIRUS-RNA EDITING - SPECIFIC MODIFICATION OF ADENOSINE INTHE ANTIGENOMIC RNA

RNA editing plays a central role in the life cycle of hepatitis D viru s (HDV), a subviral human pathogen, Previous studies (J. L. Casey, K. F. Bergmann, T. L. Brown, and J. L. Gerin, Proc. Natl, Acad, Sci USA 8 9:7149-7153, 1992; H. Zheng, T,-B, Fu, D. Lazinski, and J, Taylor, J, Virol, 66:4693-4697, 1992) had concluded that the genomic RNA of HDV w as the target for RNA editing and that the editing reaction was a conv ersion of U to C, However, we show here that the antigenomic RNA of HD V is in fact the target for HDV RNA editing, which is therefore a conv ersion of A to G, This result is verified by using an assay specific f or editing on the antigenomic RNA and by analyzing the editing of site -directed mutant RNAs in transfected cells and in cell extracts, Becau se editing occurs in the absence of viral antigens and the specificity for the HDV editing target site is present even in extracts from Dros ophila cells, it is likely that HDV RNA is edited by one or more cellu lar factors that are conserved among higher eukaryotes, These results raise the likelihood that double-stranded RNA adenosine deaminase spec ifically edits HDV antigenomic RNA.