Orchestration of the Floral Transition and Floral Development in Arabidopsis by the Bifunctional Transcription Factor APETALA2
Orchestration of the Floral Transition and Floral Development in Arabidopsis by the Bifunctional Transcription Factor APETALA2
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DOI：
10.1105/tpc.110.075606
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发表时间：
2010-07-01
期刊：
影响因子：
11.6
通讯作者：
Schmid, Markus
中科院分区：
文献类型：
--
作者：
Yant, Levi;Mathieu, Johannes;Schmid, Markus
拟南芥转录因子APETALA2（AP2）具有多种功能，包括在种子发育、干细胞维持和花器官身份的特化中的作用。为了了解这些不同作用之间的关系，我们在两种组织类型中在全基因组范围内绘制了AP 2的直接靶点。我们发现，AP2结合到数以千计的基因座在发展中的花，其中许多表现出AP2依赖的转录。相反的逻辑效应在AP 2与影响AP 2表达的两个microRNA基因结合中是明显的，AP 2正调节miR156，负调节miR172，形成复杂的直接反馈环，其还包括除了一个之外的所有AP 2样miR172靶进化枝成员。我们比较了全基因组的直接目标剧目的AP2与SCHLAFMUTZE，一个密切相关的转录因子，也抑制过渡到开花。我们检测到明确的相似性和重要的差异，也是组织特异性的直接目标剧目。最后，使用诱导表达系统，我们证明了AP 2具有双重分子作用。它同时作为转录激活因子和阻遏因子发挥作用，直接诱导花阻遏因子AGAMOUS样15的表达，并直接阻遏花激活因子如SUPPLYOR OF OVEREXPRESSION OF CONSTANS1的转录。
The Arabidopsis thaliana transcription factor APETALA2 (AP2) has numerous functions, including roles in seed development, stem cell maintenance, and specification of floral organ identity. To understand the relationship between these different roles, we mapped direct targets of AP2 on a genome-wide scale in two tissue types. We find that AP2 binds to thousands of loci in the developing flower, many of which exhibit AP2-dependent transcription. Opposing, logical effects are evident in AP2 binding to two microRNA genes that influence AP2 expression, with AP2 positively regulating miR156 and negatively regulating miR172, forming a complex direct feedback loop, which also included all but one of the AP2-like miR172 target clade members. We compare the genome-wide direct target repertoire of AP2 with that of SCHLAFMUTZE, a closely related transcription factor that also represses the transition to flowering. We detect clear similarities and important differences in the direct target repertoires that are also tissue specific. Finally, using an inducible expression system, we demonstrate that AP2 has dual molecular roles. It functions as both a transcriptional activator and repressor, directly inducing the expression of the floral repressor AGAMOUS-LIKE15 and directly repressing the transcription of floral activators like SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1.