Development of pollen, the male gametophyte of flowering plants, is tightly controlled by dynamic changes in gene expression. Recent research to clarify the molecular aspects of pollen development has revealed the involvement of several transcription factors in the induction of gene expression. However, limited information is available about the factors involved in the negative regulation of gene expression to eliminate unnecessary transcripts during pollen development. In this study, we revealed that AtNOT1 is an essential protein for proper pollen development and germination capacity. AtNOT1 is a scaffold protein of the AtCCR4-NOT complex, which includes multiple components related to mRNA turnover control in Arabidopsis. Phenotypic analysis using atnot1 heterozygote mutant pollen showed that the mature mutant pollen failed to germinate, and also revealed abnormal localization of nuclei and a specific protein at the tri-cellular pollen stage. Furthermore, transcriptome analysis of atnot1 heterozygote mutant pollen demonstrated that the down-regulation of a large number of transcripts, along with the up-regulation of specific transcripts required for pollen tube germination by AtNOT1 during late microgametogenesis, is important for proper pollen development and germination. Overall, our findings provide new insights into the negative regulation of gene expression during pollen development, by demonstrating the severely defective phonotype of atnot1 heterozygote mutant pollen.

中文翻译：

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AtNOT1是花粉发育过程中基因表达的新型调节剂。

花粉是开花植物的雄配子体，其发育受基因表达的动态变化严格控制。澄清花粉发育的分子方面的最新研究表明，一些转录因子参与了基因表达的诱导。但是，有关花粉发育过程中消除不必要的转录本的基因表达负调控所涉及的因素的信息有限。在这项研究中，我们揭示了AtNOT1是花粉发育和萌发能力的必需蛋白。AtNOT1是AtCCR4-NOT复合体的支架蛋白，其中包括与拟南芥中的mRNA转换控制相关的多种成分。使用atnot1杂合子突变体花粉的表型分析表明，成熟的突变体花粉无法发芽，并且还揭示了在三细胞花粉阶段细胞核和特定蛋白质的异常定位。此外，对atnot1杂合子突变体花粉的转录组分析表明，大量的转录本的下调，以及后期微配子发生过程中AtNOT1进行花粉管萌发所需的特定转录本的上调，对于正确的花粉发育和萌发非常重要。 。总体而言，我们的发现通过证明atnot1杂合子突变体花粉的严重缺陷表型，为花粉发育过程中基因表达的负调控提供了新的见解。atnot1杂合子突变体花粉的转录组分析表明，大量的转录本的下调，以及后期微配子发生过程中AtNOT1进行花粉管萌发所需的特定转录本的上调，对于正确的花粉发育和萌发非常重要。总体而言，我们的发现通过证明atnot1杂合子突变体花粉的严重缺陷表型，为花粉发育过程中基因表达的负调控提供了新的见解。atnot1杂合子突变体花粉的转录组分析表明，大量的转录本的下调，以及后期微配子发生过程中AtNOT1进行花粉管萌发所需的特定转录本的上调，对于正确的花粉发育和萌发非常重要。总体而言，我们的发现通过证明atnot1杂合子突变体花粉的严重缺陷表型，为花粉发育过程中基因表达的负调控提供了新的见解。