Expression Profile of Maize (Zea mays L.) Embryonic Axes During Germination: Translational Regulation of Ribosomal Protein mRNAs
Expression Profile of Maize (Zea mays L.) Embryonic Axes During Germination: Translational Regulation of Ribosomal Protein mRNAs
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DOI：
10.1093/pcp/pcr114
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发表时间：
2011-10-01
影响因子：
4.9
通讯作者：
Sanchez de Jimenez，Estela
中科院分区：
文献类型：
--
作者：
Jimenez-Lopez，Sara;Mancera-Martinez，Eder;Sanchez de Jimenez，Estela
种子萌发是植物繁殖的关键时期。在这一重要时期的基因表达的信息是相关的理解所需的成功发芽，特别是在玉米，在世界上最重要的谷物之一的主要生化过程。目前的研究集中在静止期和萌发期玉米胚阶段的差异基因表达的全球芯片分析。这项分析表明，大量的mRNA储存在静止的胚轴（QEAs）的差异调节萌发过程中的24小时发芽的胚轴（GEAs）。这些基因属于14个不同的功能类别，其中大多数对应于代谢过程，其次是运输，转录和翻译。有趣的是，编码核糖体蛋白[（r）-蛋白]的mRNA的表达，在这个快速生长期间新的核糖体形成所需的，在整个萌发过程中基本保持不变，这表明这些基因在这个发育期间在转录水平上不受调控。为了进一步研究这个问题，对来自生长刺激和非刺激的GEAs的多聚体mRNA进行了比较微阵列分析。结果显示，（r）-蛋白质mRNA在生长刺激组织的多聚核糖体中积累到高水平，表明翻译控制机制可以解释在此期间观察到的快速（r）-蛋白质合成。对（r）-蛋白mRNA的生物信息学分析表明，5′ TOP（tract of pyrimidines）样序列仅存在于上调的（r）-蛋白mRNA的5′非翻译区。这种发芽过程的整体方法可以深入了解分子变化，从而更广泛地了解在此过程中发生的调控机制。
Seed germination is a critical developmental period for plant propagation. Information regarding gene expression within this important period is relevant for understanding the main biochemical processes required for successful germination, particularly in maize, one of the most important cereals in the world. The present research focuses on the global microarray analysis of differential gene expression between quiescent and germinated maize embryo stages. This analysis revealed that a large number of mRNAs stored in the quiescent embryonic axes (QEAs) were differentially regulated during germination in the 24 h germinated embryonic axes (GEAs). These genes belong to 14 different functional categories and most of them correspond to metabolic processes, followed by transport, transcription and translation. Interestingly, the expression of mRNAs encoding ribosomal proteins [(r)-proteins], required for new ribosome formation during this fast-growing period, remains mostly unchanged throughout the germination process, suggesting that these genes are not regulated at the transcriptional level during this developmental period. To investigate this issue further, comparative microarray analyses on polysomal mRNAs from growth-stimulated and non-stimulated GEAs were performed. The results revealed that (r)-protein mRNAs accumulate to high levels in polysomes of the growth-stimulated tissues, indicating a translational control mechanism to account for the rapid (r)-protein synthesis observed within this period. Bioinformatic analysis of (r)-protein mRNAs showed that 5′ TOP (tract of pyrimidines)-like sequences are present only in the 5′-untranslated region set of up-regulated (r)-protein mRNAs. This overall approach to the germination process allows an in-depth view of molecular changes, enabling a broader understanding of the regulatory mechanisms that occur during this process.