pro1突變體中脯氨酸缺乏引起細胞周期G1到S期轉換的抑制
Pro1基因作為玉米中合成脯氨酸過程的關鍵酶，對玉米生理生化的影響是多方面且重要的。RNA-seq (Figure 5)證實pro1突變體中脯氨酸的缺乏引起了細胞周期相關基因、DNA復制相關基因以及細胞增殖相關基因表達的下調，體外添加脯氨酸后這些基因表達回復至野生型水平(Figure 6A、B)。脯氨酸作為一種重要氨基酸，它的信號分子作用會涉及細胞內部多種多樣的生理平衡和生化過程：通過GCN2，mTOR等與氨基酸缺乏偶合的調控環節，可改變細胞原有的基因表達模式，涉及蛋白合成與細胞周期等生命活動，誘導細胞進入修復，停滯或凋亡的模式。
Figure 5 Gene Expression Profiling Graphs of Wild type and pro1-ref.
(A) Graphs show log2 ratios of gene expression in 14 DAG seedlings of wild type and pro1-ref.
(B) Graphs show a scatter plot comparing gene expression in 14 DAG seedlings of wild type and pro1-ref.
(C) Graphs show genes identified as differentially expressed by Fisher’s test (red dots).
Figure 6 Cell Cycle-Related Gene Expression Analysis in Wild type and pro1-ref.
(A) RNA expression of cell cycle-related genes based on RT-PCR analysis of 14 DAG wild type and pro1-ref seedlings cultivated in 1/2 MS culture medium supplemented with various concentrations of L-proline and L-glutamate. wt, wild type; pro1, pro1-ref.
(B) Expression of various cell cycle-related genes in 14 DAG wild type and pro1-ref seedlings cultivated in 1/2 MS culture medium supplemented with various concentrations of L-proline. Ubiquitin was used as an internal control. For each sample, three technical and two independent biological replicates were performed. Error bars represent SD. wt, wild type; pro1, pro1-ref.
