Fig. 5. Effect of the disruption and overexpression of  APSI1  on the AS event of  APXII  in Arabidopsis. Semi-quantitative RT-PCR analysis detected AS variants (sAPX-II, -III, and tAPX-I mRNAs) produced from the spinach  APXII  gene in KO- apsi1 / APXII  (a) and  APSI1ox / APXII  (b) plants. Semiquantitative RT-PCR analysis (24–28 cycles) was carried out using sets of primers ( Supplementary Table 1 ) in extracts from the rosette leaves of 4-week-old plants (T3 generation). The primer positions are shown in  Fig. 1a . Amplified products were electrophoresed on a 2% (w/v) agarose gel. Equal loading of each amplified cDNA was determined using the control actin2 PCR product. M, molecular marker. The experiments were repeated at least 3 times using plants grown independently, and the representative results are shown.