Department of Plant Biology and Forest Genetics, Uppsala BioCenter Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden.
Plant Cell. 2010 Feb;22(2):349-63. doi: 10.1105/tpc.108.064816. Epub 2010 Feb 12.
The establishment and maintenance of auxin maxima in vascular plants is regulated by auxin biosynthesis and polar intercellular auxin flow. The disruption of normal auxin biosynthesis in mouse-ear cress (Arabidopsis thaliana) leads to severe abnormalities, suggesting that spatiotemporal regulation of auxin biosynthesis is fundamental for normal growth and development. We have shown previously that the induction of the SHORT-INTERNODES/STYLISH (SHI/STY) family member STY1 results in increased transcript levels of the YUCCA (YUC) family member YUC4 and also higher auxin levels and auxin biosynthesis rates in Arabidopsis seedlings. We have also shown previously that SHI/STY family members redundantly affect development of flowers and leaves. Here, we further examine the function of STY1 by analyzing its DNA and protein binding properties. Our results suggest that STY1, and most likely other SHI/STY members, are DNA binding transcriptional activators that target genes encoding proteins mediating auxin biosynthesis. This suggests that the SHI/STY family members are essential regulators of auxin-mediated leaf and flower development. Furthermore, the lack of a shoot apical meristem in seedlings carrying a fusion construct between STY1 and a repressor domain, SRDX, suggests that STY1, and other SHI/STY members, has a role in the formation and/or maintenance of the shoot apical meristem, possibly by regulating auxin levels in the embryo.
植物维管束中生长素的建立和维持受到生长素生物合成和极性细胞间生长素流的调节。在拟南芥中破坏正常的生长素生物合成会导致严重的异常,这表明生长素生物合成的时空调节对于正常的生长和发育是至关重要的。我们之前已经表明,SHORT-INTERNODES/STYLISH(SHI/STY)家族成员 STY1 的诱导导致 YUCCA(YUC)家族成员 YUC4 的转录水平升高,并且在拟南芥幼苗中也有更高的生长素水平和生长素生物合成速率。我们之前还表明,SHI/STY 家族成员冗余地影响花和叶的发育。在这里,我们通过分析 STY1 的 DNA 和蛋白质结合特性进一步研究其功能。我们的结果表明,STY1(很可能还有其他 SHI/STY 成员)是 DNA 结合转录激活因子,靶向编码介导生长素生物合成的蛋白质的基因。这表明 SHI/STY 家族成员是生长素介导的叶片和花发育的必需调节因子。此外,在携带 STY1 与抑制结构域 SRDX 之间融合构建体的幼苗中缺乏茎尖分生组织,表明 STY1(和其他 SHI/STY 成员)在茎尖分生组织的形成和/或维持中具有作用,可能通过调节胚胎中的生长素水平。