Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695, USA.
Plant Physiol. 2010 Feb;152(2):821-36. doi: 10.1104/pp.109.146183. Epub 2009 Dec 9.
Multimeric protein complexes are required during development to regulate transcription and orchestrate cellular proliferation and differentiation. The Arabidopsis (Arabidopsis thaliana) SEUSS (SEU) gene encodes a transcriptional adaptor that shares sequence similarity with metazoan Lim domain-binding transcriptional adaptors. In Arabidopsis, SEU forms a physical complex with the LEUNIG transcriptional coregulator. This complex regulates a number of diverse developmental events, including proper specification of floral organ identity and number and the development of female reproductive tissues derived from the carpel margin meristem. In addition to SEU, there are three Arabidopsis SEUSS-LIKE (SLK) genes that encode putative transcriptional adaptors. To determine the functions of the SLK genes and to investigate the degree of functional redundancy between SEU and SLK genes, we characterized available slk mutant lines in Arabidopsis. Here, we show that mutations in any single SLK gene failed to condition an obvious morphological abnormality. However, by generating higher order mutant plants, we uncovered a degree of redundancy between the SLK genes and between SLK genes and SEU. We report a novel role for SEU and the SLK genes during embryonic development and show that the concomitant loss of both SEU and SLK2 activities conditions severe embryonic and seedling defects characterized by a loss of the shoot apical meristem. Furthermore, we demonstrate that SLK gene function is required for proper development of vital female reproductive tissues derived from the carpel margin. We propose a model that posits that SEU and SLK genes support organ development from meristematic regions through two different pathways: one that facilitates auxin response and thus organ initiation and a second that sustains meristematic potential through the maintenance of SHOOTMERISTEM-LESS and PHABULOSA expression.
多聚体蛋白复合物在发育过程中是必需的，以调节转录并协调细胞增殖和分化。拟南芥（Arabidopsis thaliana）的 SEUSS（SEU）基因编码一种转录接头蛋白，与后生动物 Lim 结构域结合转录接头蛋白具有序列相似性。在拟南芥中，SEU 与 LEUNIG 转录共调节因子形成物理复合物。该复合物调节许多不同的发育事件，包括花器官身份和数量的正确特化以及由心皮边缘分生组织发育而来的雌性生殖组织的发育。除了 SEU，还有三个拟南芥 SEUSS-LIKE（SLK）基因编码假定的转录接头蛋白。为了确定 SLK 基因的功能，并研究 SEU 和 SLK 基因之间的功能冗余程度，我们在拟南芥中鉴定了现有的 slk 突变体系。在这里，我们表明，任何单个 SLK 基因突变都不能导致明显的形态异常。然而，通过生成更高阶的突变体植物，我们发现 SLK 基因之间以及 SLK 基因和 SEU 之间存在一定程度的冗余。我们报告了 SEU 和 SLK 基因在胚胎发育过程中的新作用，并表明 SEU 和 SLK2 活性的同时缺失导致严重的胚胎和幼苗缺陷，表现为顶端分生组织的丧失。此外，我们证明了 SLK 基因功能对于从心皮边缘发育而来的重要雌性生殖组织的正常发育是必需的。我们提出了一个模型，假设 SEU 和 SLK 基因通过两种不同的途径支持从分生组织区域发育器官：一种途径促进生长素反应，从而促进器官起始，另一种途径通过维持 SHOOTMERISTEM-LESS 和 PHABULOSA 的表达来维持分生组织潜能。
