Functional Analysis of Arabidopsis AtRBR1 after sucrose starvation

虽然蔗糖的可用性是至关重要的承诺，植物细胞分裂在G1期通过控制D型细胞周期蛋白的表达，它仍然不清楚这些因素如何介导进入细胞周期。在这里，我们表明，拟南芥视网膜母细胞瘤相关蛋白1（AtRBR1）参与G1期细胞周期停滞引起的蔗糖饥饿。我们构建了雌激素诱导的AtRBR1 RNA干扰（RNAi）拟南芥悬浮细胞MM2d，发现AtRBR1的下调导致蔗糖饥饿后G2期阻滞的频率更高，而非未诱导对照的G1期阻滞。AtRBR1的下调也刺激激活E2F调节的基因时，这些基因在未诱导的细胞在有限的蔗糖条件下被抑制。我们得出结论，AtRBR1是一个关键效应的蔗糖调节从G1期进展的能力。

Although sucrose availability is crucial for commitment to plant cell division during G1 phase by controlling the expression of D-type cyclins, it has remained unclear how these factors mediate entry into the cell cycle. Here we show that Arabidopsis RETINOBLASTOMA-RELATED PROTEIN 1 (AtRBR1) is involved in G1-phase cell cycle arrest caused by sucrose starvation. We generated estrogen-inducible AtRBR1 RNA interference (RNAi) Arabidopsis suspension MM2d cells, and found that downregulation of AtRBR1 leads to a higher frequency of arrest in G2 phase, instead of G1-phase arrest in the uninduced control, after sucrose starvation. Downregulation of AtRBR1 also stimulated the activation of E2F-regulated genes when these genes were repressed in the uninduced cells under the limited sucrose conditions. We conclude that AtRBR1 is a key effector for the ability of sucrose to modulate progression from G1 phase.