PDF(Pubmed)
Abstract：
CONCLUSIONS: We studied the D3-type cyclin function during gynoecium development in Arabidopsis and how they are related to the hormone cytokinin and the transcription factor SPATULA. Growth throughout the life of plants is sustained by cell division and differentiation processes in meristematic tissues. In Arabidopsis, gynoecium development implies a multiphasic process where the tissues required for pollination, fertilization, and seed development form. The Carpel Margin Meristem (CMM) is a mass of undifferentiated cells that gives rise to the gynoecium internal tissues, such as septum, ovules, placenta, funiculus, transmitting tract, style, and stigma. Different genetic and hormonal factors, including cytokinin, control the CMM function. Cytokinin regulates the cell cycle transitions through the activation of cell cycle regulators as cyclin genes. D3-type cyclins are expressed in proliferative tissues, favoring the mitotic cell cycle over the endoreduplication. Though the role of cytokinin in CMM and gynoecium development is highly studied, its specific role in regulating the cell cycle in this tissue remains unclear. Additionally, despite extensive research on the relationship between CYCD3 genes and cytokinin, the regulatory mechanism that connects them remains elusive. Here, we found that D3-type cyclins are expressed in proliferative medial and lateral tissues. Conversely, the depletion of the three CYCD3 genes showed that they are not essential for gynoecium development. However, the addition of exogenous cytokinin showed that they could control the division/differentiation balance in gynoecium internal tissues and outgrowths. Finally, we found that SPATULA can be a mechanistic link between cytokinin and the D3-type cyclins. The data suggest that the role of D3-type cyclins in gynoecium development is related to the cytokinin response, and they might be activated by the transcription factor SPATULA.
摘要：
结论：我们研究了拟南芥雌蕊发育过程中D3型细胞周期蛋白的功能，以及它们与激素细胞分裂素和转录因子SPATULA的关系。通过分生组织中的细胞分裂和分化过程来维持植物整个生命的生长。在拟南芥中,gynoecium的发育意味着一个多阶段的过程，在这个过程中，授粉所需的组织，受精,和种子发育形式。CarpelMargin分生组织（CMM）是一团未分化的细胞，可产生雌蕊内部组织，比如隔膜，胚珠,胎盘,真菌,发射道，风格,和耻辱。不同的遗传和荷尔蒙因素，包括细胞分裂素,控制CMM功能。细胞分裂素通过激活细胞周期调节因子作为细胞周期蛋白基因来调节细胞周期转换。D3型细胞周期蛋白在增殖组织中表达，有利于有丝分裂细胞周期而不是核内复制。尽管细胞分裂素在CMM和绞股蓝发育中的作用被高度研究，其在该组织中调节细胞周期的具体作用尚不清楚。此外,尽管对CYCD3基因与细胞分裂素之间的关系进行了广泛的研究，连接它们的监管机制仍然难以捉摸。这里,我们发现D3型细胞周期蛋白在增殖性内侧和外侧组织中表达。相反，这三个CYCD3基因的耗竭表明它们对于绞股蓝的发育不是必需的。然而,外源性细胞分裂素的添加表明，它们可以控制绞股蓝内部组织和外植体的分裂/分化平衡。最后,我们发现SPATULA可能是细胞分裂素和D3型细胞周期蛋白之间的机械联系。数据表明，D3型细胞周期蛋白在雌蕊发育中的作用与细胞分裂素反应有关，它们可能被转录因子SPATULA激活。
