A DE1 BINDING FACTOR 1-GLABRA2 module regulates rhamnogalacturonan I biosynthesis in Arabidopsis seed coat mucilage
A DE1 BINDING FACTOR 1-GLABRA2 module regulates rhamnogalacturonan I biosynthesis in Arabidopsis seed coat mucilage
复制标题
DE1 结合因子 1 – GLABRA2 模块调节拟南芥种皮粘液中的鼠李糖半乳糖醛酸 I 生物合成
DOI：
10.1093/plcell/koac011
复制
发表时间：
2022-01-29
期刊：
影响因子：
11.6
通讯作者：
Kong, Yingzhen
中科院分区：
文献类型：
--
作者：
Xu, Yan;Wang, Yiping;Kong, Yingzhen
水合拟南芥种子周围的粘液是一种特殊的细胞外基质，主要由果胶多糖鼠李半乳糖醛酸 I (RG-I) 组成。尽管已经鉴定了几个负责 RG-I 生物合成的基因，但控制 RG-I 产生的转录调控机制仍然很大程度上未知。在这里，我们报道三螺旋转录因子 DE1 BINDING FACTOR 1 (DF1) 是粘液 RG-I 生物合成的关键调节因子。 DF1 功能丧失突变体中 RG-I 生物合成显着减少。 DF1 与 GLABRA2 (GL2) 发生物理相互作用，并且这两种蛋白均通过转录调节 RG-I 生物合成基因 MUCILAGE MODIFIED 4 (MUM4) 和 GALACTURONOSYL TRANSFERASE-LIKE5 (GATL5) 的表达。通过染色质免疫沉淀-定量PCR和转录激活测定，我们揭示了DF1-GL2模块激活MUM4和GATL5表达的协同机制，其中DF1通过与GL2相互作用与MUM4和GATL5的启动子结合，并促进GL2的转录活性。 DF1 和 GL2 的表达受 TRANSPARENT TESTA GLABRA2 (TTG2) 直接调节，反过来，DF1 直接抑制 TTG2 的表达。综上所述，我们的数据表明，粘液 RG-I 生物合成的转录调控涉及一个调控模块，包括 DF1、DF1、GL2 和 TTG2。
The mucilage surrounding hydrated Arabidopsis thaliana seeds is a specialized extracellular matrix composed mainly of the pectic polysaccharide rhamnogalacturonan I (RG-I). Although, several genes responsible for RG-I biosynthesis have been identified, the transcriptional regulatory mechanisms controlling RG-I production remain largely unknown. Here we report that the trihelix transcription factor DE1 BINDING FACTOR 1 (DF1) is a key regulator of mucilage RG-I biosynthesis. RG-I biosynthesis is significantly reduced in loss-of-function mutants of DF1. DF1 physically interacts with GLABRA2 (GL2) and both proteins transcriptionally regulate the expression of the RG-I biosynthesis genes MUCILAGE MODIFIED 4 (MUM4) and GALACTURONOSYL TRANSFERASE-LIKE5 (GATL5). Through chromatin immunoprecipitation-quantitative PCR and transcriptional activation assays, we uncover a cooperative mechanism of the DF1-GL2 module in activating MUM4 and GATL5 expression, in which DF1 binds to the promoters of MUM4 and GATL5 through interacting with GL2 and facilitates the transcriptional activity of GL2. The expression of DF1 and GL2 is directly regulated by TRANSPARENT TESTA GLABRA2 (TTG2) and, in turn, DF1 directly represses the expression of TTG2. Taken together, our data reveal that the transcriptional regulation of mucilage RG-I biosynthesis involves a regulatory module, comprising DF1, DF1, GL2, and TTG2.