• Arabidopsis thaliana seed germination is marked by extensive translational control at two critical phase transitions. The first transition refers to the start of hydration, the hydration translational shift. The second shift, the germination translational shift (GTS) is the phase between testa rupture and radicle protrusion at which the seed makes the all or nothing decision to germinate.
• The mechanism behind the translational regulation at these phase transitions is unknown. RNA binding proteins (RBPs) are versatile players in the post-transcriptional control of messenger RNAs (mRNAs) and as such candidates for regulating translation during seed germination.
• Here, we report the mRNA binding protein repertoire of seeds during the GTS. Thirty seed specific RBPs and 22 dynamic RBPs were identified during the GTS, like the putative RBP Vacuolar ATPase subunit A and RBP HSP101. Several stress granule markers were identified in this study, which suggests that seeds are prepared to quickly adapt the translation of specific mRNAs in response to changes in environmental conditions during the GTS.
• Taken together this study provides a detailed insight into the world of RBPs during seed germination and their possible regulatory role during this developmentally regulated process.

中文翻译：

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拟南芥种子萌发过程中关键相变的mRNA结合蛋白质组

• 拟南芥种子萌发的特点是在两个关键相变处进行广泛的翻译控制。第一个转变是指水合作用的开始，即水合作用平移转变。第二个转变，萌发平移转变 (GTS) 是种皮破裂和胚根突出之间的阶段，在此阶段，种子决定发芽或完全不发芽。
• 这些相变中翻译调控背后的机制尚不清楚。RNA 结合蛋白 (RBP) 在信使 RNA (mRNA) 的转录后控制中是多才多艺的参与者，因此可以在种子萌发过程中调节翻译。
• 在这里，我们报告了 GTS 期间种子的 mRNA 结合蛋白库。在 GTS 期间鉴定了 30 个种子特异性 RBP 和 22 个动态 RBP，如推定的 RBP 液泡 ATP 酶亚基 A 和 RBP HSP101。本研究确定了几个应激颗粒标记，这表明种子准备好快速适应特定 mRNA 的翻译，以响应 GTS 期间环境条件的变化。
• 总之，这项研究提供了对种子萌发过程中 RBP 世界的详细见解，以及它们在这个发育调节过程中可能的调节作用。