Coordination of cell proliferation and cell expansion mediated by ribosome-related processes in the leaves of Arabidopsis thaliana
Coordination of cell proliferation and cell expansion mediated by ribosome-related processes in the leaves of Arabidopsis thaliana
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DOI：
10.1111/j.1365-313x.2009.03886.x
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发表时间：
2009-08-01
期刊：
影响因子：
7.2
通讯作者：
Tsukaya, Hirokazu
中科院分区：
文献类型：
--
作者：
Fujikura, Ushio;Horiguchi, Gorou;Tsukaya, Hirokazu
细胞增殖和细胞扩张的协调是决定叶大小的关键调节过程，但其分子细节尚不清楚。在拟南芥中，细胞增殖的正调控因子的突变通常会引发叶片中有丝分裂后的细胞过度扩大。这种现象被称为补偿综合征，见于突变型angustifolia 3（an 3），它在转录辅激活因子上有缺陷。然而，这种补偿并不发生在对寡细胞（oligocellula）细胞数量减少的反应中。OLI 2、OLI 5和OLI 7没有表现出补偿，并且这些突变体中细胞数量的减少是适度的。然而，当oli突变与不同oli突变组合以产生双突变体时，细胞数量进一步减少并且诱导补偿。类似地，与an 3无效突变体相比，AN 3表达的弱抑制适度地减少细胞数量，但不诱导补偿。此外，oli 2、oli 5或oli 7和an 3的双突变体显示出显著增强的补偿。这些结果表明，当由OLI 2/OLI 5/OLI 7和AN 3调节的细胞增殖以阈值依赖性方式受损时，触发补偿。OLI 2编码酿酒酵母中参与核糖体生物合成的Nop 2同系物，而OLI 5和OLI 7分别编码核糖体蛋白RPL 5A和RPL 5 B。这表明参与诱导补偿的因子可能受AN 3和核糖体相关过程的双重控制。
P>Co-ordination of cell proliferation and cell expansion is a key regulatory process in leaf-size determination, but its molecular details are unknown. In Arabidopsis thaliana, mutations in a positive regulator of cell proliferation often trigger excessive cell enlargement post-mitotically in leaves. This phenomenon, called compensation syndrome, is seen in the mutant angustifolia3 (an3), which is defective in a transcription co-activator. Such compensation, however, does not occur in response to a decrease in cell number in oligocellula (oli). oli2, oli5 and oli7 did not exhibit compensation and the reduction in cell number in these mutants was moderate. However, when an oli mutation was combined with a different oli mutation to create a double mutant, cell number was further reduced and compensation was induced. Similarly, weak suppression of AN3 expression reduced cell number moderately but did not induce compensation compared with an an3 null mutant. Furthermore, double mutants of either oli2, oli5 or oli7 and an3 showed markedly enhanced compensation. These results suggest that compensation is triggered when cell proliferation regulated by OLI2/OLI5/OLI7 and AN3 is compromised in a threshold-dependent manner. OLI2 encodes a Nop2 homolog in Saccharomyces cerevisiae that is involved in ribosome biogenesis, whereas OLI5 and OLI7 encode ribosome proteins RPL5A and RPL5B, respectively. This suggests that a factor involved in the induction of compensation may be under the dual control of AN3 and a ribosome-related process.