叶片通过由包括许多转录因子的基因调控网络控制的不同阶段生长。拟南芥同源框12(ATHB12)促进叶片生长,尤其是在细胞扩增阶段。在这项研究中,我们鉴定了TCP转录因子家族的成员TCP13,作为ATHB12的上游抑制剂。使用ATHB12的1.2kb上游区域的酵母单杂交筛选导致TCP13以及其他转录因子的分离。组成型表达TCP13的转基因植物表现出叶细胞大小的显着减少,特别是在细胞扩增期间,而抑制TCP13及其旁系同源物(TCP5和TCP17)导致增大的叶细胞,表明TCP13及其旁系同源物抑制叶片发育,主要在细胞扩增阶段。其在叶片扩张阶段的表达模式与ATHB12表达相反。始终如一,当TCP13过表达时,ATHB12及其下游基因的表达降低,并且当TCP13及其旁系同源物的表达被抑制时增加。在使用TCP13-GFP植物的染色质免疫沉淀测定中,含有TCP结合的共有序列的ATHB12上游区域的片段被强烈富集。一起来看,这些发现表明TCP13及其旁系同源物通过抑制ATHB12表达来抑制叶片生长。
Leaves grow by distinct phases controlled by gene regulatory networks including many transcription factors. Arabidopsis thaliana homeobox 12 (ATHB12) promotes leaf growth especially during the cell expansion phase. In this study, we identify
TCP13, a member of the TCP transcription factor family, as an upstream inhibitor of ATHB12. Yeast one-hybrid screening using a 1.2-kb upstream region of ATHB12 resulted in the isolation of
TCP13 as well as other transcription factors. Transgenic plants constitutively expressing
TCP13 displays a significant reduction in leaf cell size especially during the cell expansion period, while repression of
TCP13 and its paralogs (TCP5 and TCP17) result in enlarged leaf cells, indicating that TCP13 and its paralogs inhibit leaf development, mainly at the cell expansion phase. Its expression pattern during leaf expansion phase is opposite to ATHB12 expression. Consistently, the expression of ATHB12 and its downstream genes decreases when TCP13 was overexpressed, and increases when the expression of
TCP13 and its paralogs is repressed. In chromatin immunoprecipitation assays using TCP13-GFP plants, a fragment of the ATHB12 upstream region that contains the consensus sequence for TCP binding is strongly enriched. Taken together, these findings indicate that TCP13 and its paralogs inhibit leaf growth by repressing ATHB12 expression.