Multiple domains in a ribozyme construct confer increased suppressive activity in monkey cells.

An expression vector designed to express a long (approximately 1 kb) RNA containing multiple ribozyme domains was cotransfected into mammalian cells with a plasmid encoding, as target, messenger RNA for chloramphenicol acetyltransferase (CAT). In comparative studies the multimeric ribozyme construct proved to be significantly more effective at suppressing CAT expression than either the corresponding antisense RNA, or a transcript carrying a single ribozyme domain. Suppression of gene activity was apparently specific because expression of an independently expressed gene for human growth hormone was unaffected. The profile of CAT RNA extracted from transfected cells was consistent with RNA cleavage.