Figure 1.

RT-PCR Analysis of ATG8 and ATG4 Expression in Arabidopsis.

(A) and (C) Total cellular RNA from roots (R), stems (St), leaves (L), flowers (F), and siliques (Si) of wild-type Arabidopsis grown hydroponically for 4 to 5 weeks was isolated and subjected to RT-PCR using gene-specific primers. The RT-PCR was terminated after 35 cycles for all the reactions, and the products were electrophoresed and detected.

(B) and (D) Wild-type Arabidopsis were grown for 5 weeks in nutrient-rich hydroponic medium (7 mM nitrate) and then transferred to nitrogen-depleted hydroponic medium (0 mM nitrate) for 1 d. Total cellular RNA from leaves after 1, 3, 6, and 12 h of nitrogen starvation was isolated and subjected to quantitative RT-PCR (B) or semiquantitative RT-PCR (D). The amounts of transcripts were presented as arbitrary units. Semiquantitative RT-PCR was terminated after 22 cycles for ATG4a and ATG4b and 20 cycles for UBQ10. The products were electrophoresed and detected. The ubiquitin gene, UBQ10, which is constitutively expressed under all conditions, was used as an internal control for RNA level.