Figure 1.

G2/M phase-specific genes are up-regulated by the overexpression of the truncated version of NtmybA2. A, Up-regulation of G2/M phase-specific genes in transgenic calli carrying 35S∷NtmybA2ΔC. Tobacco BY-2 cells were transformed with the vector alone (Control), 35S∷NtmybA2, and 35S∷NtmybA2ΔC by the Agrobacterium-mediated method. Total RNA was extracted from the transformed calli that were generated on the selection agar medium. Real-time RT-PCR analysis was performed to quantify the transcript abundance of the G2/M phase-specific genes (NtKN, CYCB1;3, and NACK1). In addition, the CDKA gene, which is constitutively expressed during the cell cycle, was analyzed in the same way as the control. B, Up-regulation of G2/M phase-specific genes in 35S∷NtmybA2ΔC cells during the stationary phase in cell suspension cultures. Cell suspension cultures were established from transformed BY-2 cells carrying the vector alone (Control), 35S∷NtmybA2, and 35S∷NtmybA2ΔC. For each construct, total RNA was extracted from cells on day 3 (logarithmic phase) and day 7 (stationary phase) after subculture. Transcript abundance of the G2/M phase-specific genes was determined by real-time RT-PCR analysis. Two S phase-specific genes, PCNA and CYCA3;1, were analyzed in the same way for comparison. In both A and B, the results of the real-time PCR were normalized to the expression of EF1α mRNAs. The relative transcript levels were averaged over the three biological replicates and are shown with the sds (error bars).