Monitoring of rbcL gene expression in plant tissues using the electrochemical enzyme-linked DNA hybridization assay. (A), scheme of the experiment. RT-PCR: total RNA isolated from tobacco tissues was reversely transcribed (RT) into cDNA using random primers, followed by PCR amplification of the rbcL gene fragment (frrbcL) using specific primers (see ). Genomic DNA PCR: the frrbcL fragment was amplified from total tobacco genomic DNA. (B), bar graph showing intensities of peak N obtained for the PCR products: (1-2), RT-PCR; (3-4), genomic DNA PCR; (1,3), green leaves; (2,4), non-green callus. The hybridization assays were performed as in using biotinylated prbcL probe; controls: “non specific amplicon”, frp53 was used as tDNA; “no probe”, frrbcL (resulting from RT-PCR of the green plant sample) was used as tDNA but no probe was subsequently added. (C), agarose gel electrophoresis of the PCR products 1-4 (the same numbering as in B).