Cui Hongchang, Levesque Mitchell P, Vernoux Teva, Jung Jee W, Paquette Alice J, Gallagher Kimberly L, Wang Jean Y, Blilou Ikram, Scheres Ben, Benfey Philip N
Department of Biology and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA.
Science. 2007 Apr 20;316(5823):421-5. doi: 10.1126/science.1139531.
Intercellular protein movement plays a critical role in animal and plant development. SHORTROOT (SHR) is a moving transcription factor essential for endodermis specification in the Arabidopsis root. Unlike diffusible animal morphogens, which form a gradient across multiple cell layers, SHR movement is limited to essentially one cell layer. However, the molecular mechanism is unknown. We show that SCARECROW (SCR) blocks SHR movement by sequestering it into the nucleus through protein-protein interaction and a safeguard mechanism that relies on a SHR/SCR-dependent positive feedback loop for SCR transcription. Our studies with SHR and SCR homologs from rice suggest that this mechanism is evolutionarily conserved, providing a plausible explanation why nearly all plants have a single layer of endodermis.
细胞间蛋白质移动在动植物发育过程中起着关键作用。SHORTROOT（SHR）是一种移动转录因子，对拟南芥根中内皮层的特化至关重要。与在多个细胞层中形成梯度的可扩散动物形态发生素不同，SHR的移动基本上局限于一个细胞层。然而，其分子机制尚不清楚。我们发现，稻草人（SCR）通过蛋白质-蛋白质相互作用将SHR隔离到细胞核中，以及一种依赖SHR/SCR的SCR转录正反馈环的保障机制，从而阻止SHR移动。我们对水稻中SHR和SCR同源物的研究表明，这种机制在进化上是保守的，这为几乎所有植物都有单层内皮层提供了一个合理的解释。
