Figure 1.

The hairpin ribozyme library and gene vector. (A) Sequence and secondary structure of the hairpin ribozyme (capital letters), bound to its target RNA (lowercase letters). Both target-binding arms (helices 1 & 2) are randomized, generating a library with as many as 4¹² different catalytic molecules (ribozymes). (B) Schematic representation of the retroviral vector following insertion of the ribozyme library DNA template. Ribozyme expression is driven by the tRNA^val promoter. (C) Flow cytometry for EGFP of SK-BR-3, PA-1, and T47-D cells. Numbers in parentheses indicate the relative expression levels of endogenous BRCA1. Analysis of untransfected control cells (parental cells) and dilution clones from cells, transfected with pBR-EGFP (BR-EGFP) or with pCMV-EGFP (CMV-EGFP).