We have experimentally shown here, for the first time, that programmed À1 frameshifting is present in the Archaea domain. This finding is the missing piece in the puzzle of the phylogenetic distribution of programmed frameshifting demonstrating that this mechanism is universally conserved. Role of RNA helicases in HIV-1 replication Viruses are replication competent genomes which are relatively gene-poor. Even the largest viruses (i.e. Herpesviruses) encode only slightly >200 open reading frames (ORFs). However, because viruses replicate obligatorily inside cells, and considering that evolution may be driven by a principle of economy of scale, it is reasonable to surmise that many viruses have evolved the ability to co-opt cell-encoded proteins to provide needed surrogate functions. An in silico survey of viral sequence databases reveals that most positive-strand and double-stranded RNA viruses have ORFs for RNA helicases. On the other hand, the genomes of retroviruses are devoid of virally-encoded helicase. Here, we review in brief the notion that the human immunodeficiency virus (HIV-1) has adopted the ability to use one or more cellular RNA helicases for its replicative life cycle. Helicases are enzymes that separate in an energy-dependent manner stretches of duplexed DNA and/or RNA into singlestranded components. Currently, based on characteristic motifs and the sequence comparisons, three superfamilies (SF1 through 3) and two smaller families (F4, F5) of helicases have been identified (1) . Superfamily 1 and 2 contain helicases which share seven or more recognized signature amino acid motifs while SF3 and F4 and F5 helicases are characterized generally by three conserved motifs (2) ; the F4 and F5 proteins are largely bacterial and bacteriophage proteins. Currently, it should be cautioned that many 'helicases' are not bona fide helicases, but may only function as RNA translocases, perhaps to fulfill functions in the remodeling of ribonucleoprotein complexes (RNP).