Interplay between m6A modification and overall transcripts quantity: Impacts on mRNA composition in plant stress granules
Interplay between m6A modification and overall transcripts quantity: Impacts on mRNA composition in plant stress granules
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DOI：
10.1101/2023.12.14.569339
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发表时间：
2023-12
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影响因子：
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通讯作者：
D. Kubiak;M. Szcześniak;Karolina Ostrowska;D. Bielewicz;S. S. Bhat-S.;K. Niedojadło;Z. Szweykowska-Kulińska;A. Jarmolowski;R. Fray;J. Niedojadlo
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作者：
D. Kubiak;M. Szcześniak;Karolina Ostrowska;D. Bielewicz;S. S. Bhat-S.;K. Niedojadło;Z. Szweykowska-Kulińska;A. Jarmolowski;R. Fray;J. Niedojadlo
应力颗粒（SGs）是在不利环境条件下产生的细胞质结构。它们含有丰富的RNA，包括未翻译的mRNA。控制转录本在SGs中积累的机制仅部分了解。尽管已知m6A在植物转录组调控中的作用，但其对SGs组成和组装的影响尚不清楚。我们研究了在缺氧条件下，在Lupinus angustifolius和拟南芥（Arabidopsis thaliana）根中SGs颗粒的形成、m6A的存在以及这些颗粒中选定mrna的转录水平依赖性定位。在羽扇豆中，SGs表现出独特的双区结构，由一个环和一个中心区域组成，其超微结构和组成不同。转录组分析后，选择mrna进行SGs和m6A水平定位检查。与管家基因相比，对缺氧反应的基因（ADH1和HUP7）的转录本显示出明显较低的m6A水平，但在SGs中只有ADH1不存在。HUP7 mRNA在SGs和细胞质中均存在，m6A含量较低，可能是由于其表达量极高。结果还表明，仅在缺氧的前几个小时，SGs中m6A的含量高于细胞质中m6A的含量，随后下降。在m6A水平降低的拟南芥突变体中，研究了SGs的形成和数量。在这条线上，没有观察到ECT2， poly(A) RNA水平在SGs中略有降低。此外，SGs数量也低于野生型。总之，我们的研究结果表明m6A修饰对SGs组装的影响有限。然而，m6A修饰与细胞质中转录总量之间的相互作用在mRNA向SGs的分配中起着调节作用。
Stress granules (SGs) are cytoplasmic structures that emerge in response to unfavorable environmental conditions. They contain a rich pool of RNA, including non-translated mRNA. The mechanisms governing transcripts accumulation in SGs is only partially understood. Despite the recognized role of m6A in plant transcriptome regulation, its impact on SGs’ composition and assembly remains elusive. We examined the formation of SGs, the presence of m6A, and the transcription-level-dependent localization of selected mRNAs within these granules during hypoxia in the roots of Lupinus angustifolius and Arabidopsis thaliana. In lupine, SGs exhibit a distinctive bi-zonal structure, comprising of a ring and a central area with differences in ultrastructure and composition. Following the transcriptome analysis, mRNAs were selected for examination of their localization in SGs and m6A levels. Transcripts from genes responsive to hypoxia (ADH1 and HUP7) exhibited significant lower levels of m6A compared to housekeeping genes but only ADH1 was not present in SGs. HUP7 mRNA with low quantity of m6A, is present both in the SGs and cytoplasm probably due to extremely high expression level. It was also shown that the amount of m6A in SGs was higher than in the cytoplasm only in the first hours of hypoxia and then decreased. In mutants of A. thaliana with reduced level of m6A, formation and quantity of SGs were studied. In this line, ECT2 was not observed and poly(A) RNA levels were slightly reduced in SGs. Additionally the number of SGs was lower than that of the wild type. In summary, our findings demonstrate the limited impact of m6A modification on SGs assembly. However the interplay between m6A modification and the overall transcript quantity in the cytoplasm plays a regulatory role in mRNA partitioning into SGs.