BASE CHANGES AT POSITION-1014 AND POSITION-578 OF DELTA-VIRUS RNA IN GREEK ISOLATES MAINTAIN BASE-PAIR IN ROD CONFORMATION WITH EFFICIENT RNA EDITING

Analysis of delta hepatitis virus (HDV) genomic RNA, derived from Gree k patients from an area where HDV infection is associated with low pat hogenicity, is described. In all isolates sequenced, which included 18 /18 HDV cDNA clones derived from 6 different patients, irrespective of pathogenicity, a base change (T-->C) was found in position 1014. No s ignificant differences in editing efficiency were found between isolat es from inactive and active forms of the disease, although L-antigen w as present in low to undetectable levels in the serum of 5/6 patients. An additional mutation was identified at position 578 (A-->G), which reestablishes the canonical base pair GIC with the mutated 1014 when t he genome adopts the ''rod-like'' conformation. This finding supports the presence of this genome conformation in vivo and the requirement f or the Watson-Crick base pair 1014/ 578. A mutation, found at amino ac id position 170 (serine-->asparagine), appears to segregate with patie nts with inactive disease. (C) 1995 Wiley-Liss, Inc.