Amylose content is a crucial physicochemical property responsible for the eating and cooking quality of rice (Oryza sativa L.) grain and is mainly controlled by the Waxy (Wx) gene. Previous studies have identified several Dull genes that modulate the expression of the Wx^b allele in japonica rice by affecting the splicing efficiency of the Wx^b pre-mRNA. Here, we uncover dual roles for a novel Dull gene in pre-mRNA splicing and microRNA processing. We isolated the dull mutant, du13, with a dull endosperm and low amylose content. Map-based cloning showed that Du13 encodes a C₂H₂ zinc-finger protein. Du13 coordinates with the nuclear cap-binding complex to regulate the splicing of Wx^b transcripts in rice endosperm. Moreover, Du13 also regulates alternative splicing of other protein-coding transcripts and affects the biogenesis of a subset of microRNAs. Our results reveal an evolutionarily conserved link between pre-mRNA splicing and microRNA biogenesis in rice endosperm. Our findings also provide new insights into the functions of Dull genes in rice and expand our knowledge of microRNA biogenesis in monocots.

中文翻译：

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Du13 编码一种 C2H2 锌指蛋白，可调节水稻胚乳中 Wxb 前 mRNA 剪接和 microRNA 生物发生

直链淀粉含量是决定大米 ( Oryza sativa L.) 谷物食用和烹饪质量的关键物理化学性质，主要由Waxy ( Wx ) 基因控制。以前的研究已经确定了几个通过影响Wx ^b pre-mRNA的剪接效率来调节粳稻中Wx ^b等位基因表达的Dull基因。在这里，我们揭示了一种新的Dull基因在前 mRNA 剪接和 microRNA 加工中的双重作用。我们分离出沉闷的突变体du13，胚乳无光泽，直链淀粉含量低。基于图谱的克隆显示Du13编码 C ₂ H ₂锌指蛋白。Du13 与核帽结合复合物协调以调节水稻胚乳中Wx ^{b转录物的剪接。}此外，Du13 还调节其他蛋白质编码转录物的可变剪接并影响 microRNA 子集的生物发生。我们的研究结果揭示了水稻胚乳中前 mRNA 剪接和 microRNA 生物发生之间的进化保守联系。我们的研究结果还为水稻中Dull基因的功能提供了新的见解，并扩展了我们对单子叶植物中 microRNA 生物发生的认识。