Figure 7 Evidence of Aberrant Cell Cycle in pro1-ref.
(A) Cell cycle analysis of 14 DAG seedlings of wild type, pro1-ref and pro1-ref cultivated on medium supplemented with 3 mM L-proline. wt, wild type; pro1, pro1-ref.
(B) Cell cycle analysis of 18 DAP endosperms of wild type and pro1-ref. wt, wild type; pro1, pro1-ref.
(C) Cell cycle analysis of 24 DAP endosperms of wild type and pro1-ref. wt, wild type; pro1, pro1-ref.
The small graphs (I, II, and III) inserted in A, B, and C respectively are the cell cycle diagrams of 14 DAG seedlings, 18 and 24 DAP endosperms analyzed by flow cytometry. The 2C and 4C are DNA contents of the nuclei at stage G1 and S phase of 14 DAG seedlings respectively. The 3C and 6C are DNA contents of the nuclei at stage G1 and S phase of 18 and 24 DAP endosperms. The 12C and >= 24C are DNA contents of endoreduplicated nuclei at stage S phase of 18 and 24 DAP endosperms. For each sample, three independent biological replicates were performed. Bars represent average values ± SD, n=3 replicates (No refers to P > 0.05, * refers to P < 0.05, ** refers to P < 0.01, Student’s test).
用流式細胞儀進行細胞周期分析表明，與野生型相比，pro1-ref幼苗的細胞周期受到抑制，表現為4C DNA減少，相應的2C DNA增多，可能DNA擴增受到抑制(Figure 7A)。將pro1-ref突變體與野生型幼苗在萌發后移至含3mM的L-脯氨酸中培養9-10天，收取整苗進行細胞周期分析，結果表明，在3mM的L-脯氨酸中培養的pro1-ref突變體幼苗細胞周期基本恢復至野生型水平(Figure 7A)。籽粒胚乳細胞的細胞周期分析進一步證實了G1到S期轉換的抑制(Figure 7B和C)。這些結果表明，pro1-ref突變體中L-脯氨酸的缺乏抑制了細胞周期，外源添加L-脯氨酸可以促進pro1-ref突變體的細胞周期恢復正常。
Pro1基因功能的解析，有助于了解脯氨酸在植物生長與發育中的調控作用機理，進而更全面地理解它在細胞生命活動過程中的重要作用，使人們對脯氨酸的功能有了新的認識。