A Virus Model for Examining the Intracellular Efficiency of a Ribozyme Targeted to HIV-1

An approach that assesses the intracellular efficiency of ribozyme cleavage of HIV RNA is described. A viral replicon that contains both a ribozyme and its target sequence was constructed and tested for viability inside T lymphocytes. The viral replicon is an intact HIV- 1 genome into which we have engineered an RNA sequence that cleaves an RNA site in the HIV-1 U5. When this molecule was introduced into HeLa CD4 + cells followed by co-cultivation with MT4 cells, virus replication was initially inhibited, while control HIV-1 cultures showed normal growth kinetics. However, after several days in culture, virus production was observed from this HIV–U5–ribozyme molecule. This finding suggests that in this context a U5 ribozyme cannot permanently suppress HIV-1 production. This HIV ribozyme-containing model is useful for determining the intracellular efficiency of ribozymes targeted to different sites in the HIV genome. It could be used also to examine the nature and mechanism of resistance by HIV to ribozymes.