SEQUENCE HETEROGENEITY IN THE TERMINI OF LYMPHOCYTIC CHORIOMENINGITISVIRUS GENOMIC AND ANTIGENOMIC RNAS

Sequence analysis of lymphocytic choriomeningitis virus L and S RNAs h as revealed evidence of heterogeneity within the termini of the genomi c and antigenomic RNAs. The RNAs are missing from 0 to 38 bases, show characteristic patterns of deleted nucleotides at both 5' and 3' termi ni, and often have a nontemplated base at the terminus. The same delet ions, at either the 5' or the 3' terminus of the genomic L and S RNAs, are frequently found in the complementary strand of antigenomic RNA, suggesting that RNAs with deleted termini may be recognized as functio nal templates for replication. RNAs extracted from virions, or viral n ucleocapsids isolated from acutely infected cells, are similar in the nature and extent of terminal heterogeneity that have been observed. T his finding brings into question the function of the conserved sequenc es located at the termini of arenavirus genomic RNAs. Our data suggest that, while replication and packaging of the genomic and antigenomic RNA molecules can occur with terminally deleted molecules, mature tran scripts may be derived only from full-length templates containing the conserved terminal sequence.