AN RNA STEM-LOOP STRUCTURE INVOLVED IN THE PACKAGING OF BOVINE LEUKEMIA-VIRUS GENOMIC RNA IN-VIVO

An RNA secondary structure of the bovine leukemia virus (BLV) 5'-termi nal RNA sequence was constructed by computer-assisted RNA secondary st ructure analysis. Mutations were created in the noncoding region (NCR) of BLV, which contains a conserved consensus sequence, to disrupt pre dicted secondary structure of this region. After transfection of these constructs into FLK-BLV cells and analysis oi viral particles a reduc tion in mutant RNA content was observed relative to that of unmutated vector RNA. The packaging efficiency of the mutant with a substitution in the consensus sequence was reduced threefold and that of the mutan t with a deleted 5' NCR was reduced fivefold. We conclude that predict ed RNA secondary structure and/or nucleotide sequence of the BLV nonco ding region is essential for BLV RNA packaging in vivo. (C) 1995 Acade mic Press, Inc.