RT-PCR analysis in untransformed tissues of the cultivar 'Three Hand Planty' at 26°C (26) and 8°C (8) treatments for the housekeeping actin gene ( act ) and the different 3'-tagged sequences of line 17. Actin primers flank an intron allowing discrimination between a genomic DNA product (225 bp) and the cDNA product (150 bp). Transcription of the 3'-tagged sequences 17-1, 17-2, 17-3 and 17-4 of line 17 was verified employing the sequence-specific primer pairs 17-RTLB-1/17-LinkLB-1R, 17-RTLB-2/17LinkLB-2R, 17-RTLB-3/17-Link-3R and 17-RTLB-4/17-linkLB-4R, respectively. Cell col: cell colonies (developmental stage I). Le (leaf tissue) and Ro (root tissue) from in vitro plants (developmental stage III). RT: room temperature (25 ± 2°C). C: water control in cDNA synthesis. MQ: water control in the PCR reaction. PCR performed on RNA was negative for all the primer combinations (data not shown). MW: SmartLadder SF (Eurogentec, Seraing, Belgium).