The schematic structure of the CtsB-BioShuttle (upper part) accentuates the modular construction which consists of the following functional units: CPP module (red) is responsible for the passage across cell membranes (the amino acid sequence is shown in the column F). The PNA module (yellow) harbours the sequences for the hybridization (column D, line 1 - antisense; line 2 - sense; line 3 - random) with the target-sequence inside of the CtsB mRNA's Exon I. After the enzymatic cleavage % (red) of the disulfide bridge (column E) inside of the cytosol, the CtsB cleavage module (column C, highlighted in grey) & covalently coupled to the NLS module (column B, red/blue) is cut. This in turn is connected to the Rhod110 (column A) fluorescent dye as a cargo (green) is illustrated. In the lines 1-3 the BioShuttle conjugates used for experiments are described.