Tailoring the switch from IRES-dependent to 5′-end-dependent translation with the RNase P ribozyme

Levels of IRES-dependent translation in response to coexpression of the rnpB ribozyme with the Lb protease. (A) BHK-21 cells were transfected with the pBIC IRES construct (0.2 μg/10⁵ cells) in the presence or absence of the Lb-expression plasmid (0.033 μg/10⁵ cells). Extracts prepared at 4 and 8 hpt were used to measure CAT (IRES construct) or luciferase (all constructs). (B) Levels of luciferase activity found in the ribozyme-IRES constructs were made relative to those detected in the extract corresponding to the control IRES vector (54497300 RLU 4 hpt, 164576200 RLU 8 hpt), set to 100%.