背景回顾：Plant cells exhibit remarkable plasticity of their differentiation states, enabling regeneration of whole plants from differentiated somatic cells. 

提出问题：How they revert cell fate and express pluripotency, however, remains unclear. 

主要发现：In this study we demonstrate that transcriptional activation of auxin biosynthesis is crucial for reprogramming differentiated Arabidopsis (Arabidopsis thaliana) leaf cells. 

结果1-乙酰化-PLTs-YUC1-生长素生物合成：Our data show that interfering with the activity of histone acetyltransferases dramatically reduces callus formation from leaf mesophyll protoplasts. Histone acetylation permits transcriptional activation of PLETHORAs (PLTs), leading to the induction of their downstream YUCCA1 (YUC1) gene encoding an enzyme for auxin biosynthesis.  

结果2-生长素-ARF/IAA-MYB3Rs-细胞周期：Auxin biosynthesis is in turn required to accomplish initial cell division through the activation of G2/M phase genes mediated by MYB DOMAIN PROTEIN 3-RELATED (MYB3Rs). We further show that the AUXIN RESPONSE FACTOR 7 (ARF7)/ARF19 and INDOLE-3-ACETIC ACID INDUCIBLE 3 (IAA3)/IAA18-mediated auxin signaling pathway is responsible for cell cycle reactivation by transcriptionally upregulating MYB3R4. 

结论：These findings provide a mechanistic model of how differentiated plant cells revert their fate and reinitiate the cell cycle to become pluripotent. 

 摘 要 

处于分化状态的植物细胞仍具有超强的可塑性，能够由已分化的体细胞再生出一颗完整的植株。但是，植物体细胞是如何逆转细胞命运，从而获得多能性的，这一点还不清楚。本文中，作者发现生长素生物合成的转录激活对于重编程拟南芥已分化的叶片细胞至关重要。作者发现，干扰组蛋白乙酰转移酶的活性，能够显著减少拟南芥由叶肉原生质体为外植体诱导形成的愈伤。组蛋白乙酰化能够促进PLTs基因的转录激活，从而诱导其下游靶基因YUC1的表达，而YUC1基因编码的酶正是作用于生长素的生物合成。接着，生长素生物合成通过MYB3Rs介导的G2/M期基因激活，完成初始的细胞分裂。作者进一步的研究发现，生长素响应因子ARF7/19和IAA3/18介导的生长素信号转导途径作用于MYB3R4介导的细胞周期重激活。本文的研究结果揭示了一个分子模型，解释了已分化的植物细胞如何逆转自身的发育命运，并起始细胞周期从而获得多能性。

 Keiko Sugimoto