Aguilar-Martínez José Antonio, Uchida Naoyuki, Townsley Brad, West Donnelly Ann, Yanez Andrea, Lynn Nafeesa, Kimura Seisuke, Sinha Neelima
Department of Plant Biology, University of California, Davis, California 95616 (J.A.A.-M., N.U., B.T., D.A.W., A.Y., N.L., S.K., N.S.);World Premier International Research Center Initiative-Institute of Transformative Bio-Molecules, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan (N.U.); andDepartment of Bioresource and Environmental Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan (S.K.).
Department of Plant Biology, University of California, Davis, California 95616 (J.A.A.-M., N.U., B.T., D.A.W., A.Y., N.L., S.K., N.S.);World Premier International Research Center Initiative-Institute of Transformative Bio-Molecules, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan (N.U.); andDepartment of Bioresource and Environmental Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan (S.K.)
Plant Physiol. 2015 Feb;167(2):424-42. doi: 10.1104/pp.114.248625. Epub 2014 Dec 18.
The activity of SHOOT MERISTEMLESS (STM) is required for the functioning of the shoot apical meristem (SAM). STM is expressed in the SAM but is down-regulated at the site of leaf initiation. STM is also required for the formation of compound leaves. However, how the activity of STM is regulated at the transcriptional, posttranscriptional, and posttranslational levels is poorly understood. We previously found two conserved noncoding sequences in the promoters of STM-like genes across angiosperms, the K-box and the RB-box. Here, we characterize the function of the RB-box in Arabidopsis (Arabidopsis thaliana). The RB-box, along with the K-box, regulates the expression of STM in leaf sinuses, which are areas on the leaf blade with meristematic potential. The RB-box also contributes to restrict STM expression to the SAM. We identified FAR1-RELATED SEQUENCES-RELATED FACTOR1 (FRF1) as a binding factor to the RB-box region. FRF1 is an uncharacterized member of a subfamily of four truncated proteins related to the FAR1-RELATED SEQUENCES factors. Internal deletion analysis of the STM promoter identified a region required to repress the expression of STM in hypocotyls. Expression of STM in leaf primordia under the control of the JAGGED promoter produced plants with partially undifferentiated leaves. We further found that the ELK domain has a role in the posttranslational regulation of STM by affecting the nuclear localization of STM.
茎尖分生组织（SAM）的功能需要无茎尖分生组织（STM）的活性。STM在SAM中表达，但在叶原基起始部位表达下调。STM对于复叶的形成也是必需的。然而，STM的活性在转录、转录后和翻译后水平是如何被调控的，目前还知之甚少。我们之前在被子植物的STM类基因启动子中发现了两个保守的非编码序列，即K盒和RB盒。在这里，我们描述了拟南芥中RB盒的功能。RB盒与K盒一起，在叶窦（叶片上具有分生组织潜能的区域）中调节STM的表达。RB盒也有助于将STM的表达限制在SAM中。我们鉴定出FAR1相关序列相关因子1（FRF1）是RB盒区域的结合因子。FRF1是与FAR1相关序列因子相关的四个截短蛋白亚家族中的一个未被表征的成员。STM启动子的内部缺失分析确定了一个在胚轴中抑制STM表达所需的区域。在锯齿状启动子控制下，STM在叶原基中的表达产生了具有部分未分化叶片的植株。我们进一步发现，ELK结构域通过影响STM的核定位，在STM的翻译后调控中发挥作用。
