Extended Data Fig. 6: TOP1a regulates cell cycle gene expression.

a, Heatmap showing the expression of cell-cycle-related genes in WT and top1α ± AZD-8055 treatment. b, RT-qPCR of CYCD3;3 and E2Fa as well as E2Fa target gene expression in WT and top1α under the indicated treatments. Gene expression in WT –Suc was set to 1. Data represent mean ± s.d. of 3 biological repeats. Statistical significance was determined by one-way ANOVA and Tukey test (P < 0.05) (see Supplementary Data 1 for specific P values). c, Diagram of the CYCD3;3 locus. Gray and black rectangles and black lines represent untranslated regions, coding regions, and introns, respectively. Two nucleotides (GA) were deleted, resulting in a premature stop codon (red), in the cycd3;3 mutant. d, e, Quantification of CSC layer (d) and CC number (e) of the indicated genotypes. Data represent mean ± s.d. of 3 biological repeats (d). Data were analyzed from 15 seedlings for each genotype from 3 experiments (e). Statistical significance was determined by one-way ANOVA and Tukey test (P < 0.05) (see Supplementary Data 1 for specific P values). f, Root gravity responses and amyloplast formation in the indicated genotypes. Seedlings were turned 90° from the vertical axis and fixed at the indicated time points. Amyloplast formation and levels in layers S1 and S2 were examined. Yellow lines represent amyloplast levels, white stars mark the QC, green arrows mark the CSC layer, white arrows mark amyloplast in CSC. (m/n) indicates m in n of biological repeats showing the displayed features. Scale bar: 25 µm.