Variation in mitochondrial transcript profiles of protein-coding genes during early germination and seedling development in wheat
Variation in mitochondrial transcript profiles of protein-coding genes during early germination and seedling development in wheat
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DOI：
10.1007/s00294-004-0544-2
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发表时间：
2004-12-01
期刊：
影响因子：
2.5
通讯作者：
Bonen, L
中科院分区：
文献类型：
--
作者：
Li-Pook-Than, J;Carrillo, C;Bonen, L
我们检查了种子离开休眠、发芽和发育成幼苗的发育时期小麦线粒体基因的 RNA 谱。使用编码特异性和内含子特异性探针对吸胀后 0 小时至 6 天分离的线粒体 RNA 进行 Northern 分析。在休眠种子中观察到稳定的、经过编辑的 mRNA，随后在胚胎萌发早期检测到前体 RNA。呼吸链基因（nad7、cox1、cox2、atp6）显示的 mRNA 谱与核糖体 RNA 的 mRNA 谱相似，而核糖体蛋白基因（rps2、rps3、rps7）在幼苗发育的后期阶段具有相应较低的稳态 mRNA 水平。与各自的 mRNA 相比，前体的相对水平在发育过程中下降，这与早期阶段转录速度超过 RNA 加工的情况一致，但在吸收几天后协调更加有效。在含有第二组内含子的多重分裂基因的情况下，观察到剪接中间体的复杂模式，表明内含子去除缺乏严格的极性，尽管内含子之间的剪接效率似乎不同。切除的内含子 RNA 在胚胎中通常比幼苗中相对更丰富。这些观察结果与种子萌发开始时 RNA 加工机制的短暂不平衡是一致的，种子萌发是线粒体快速生物发生的时期。
We examined RNA profiles of wheat mitochondrial genes during the developmental period when seeds leave dormancy, germinate and develop into seedlings. Mitochondrial RNAs isolated from 0 h to 6 days post-imbibition were subjected to Northern analysis, using coding-specific and intron-specific probes. Stable, edited mRNAs were observed in dormant seeds and precursor RNAs were subsequently detected early in embryo germination. The respiratory chain genes (nad7, cox1, cox2, atp6) showed mRNA profiles which paralleled those of the ribosomal RNAs, whereas ribosomal protein genes (rps2, rps3, rps7) had proportionately lower steady-state mRNA levels in later stages of seedling development. The relative levels of precursors compared with the respective mRNAs shifted down during development, consistent with transcription outpacing RNA processing in the early stages but co-ordination being more effective several days after imbibition. In the case of multiply split genes containing group II introns, complex patterns of splicing intermediates were observed, suggesting a lack of strict polarity of intron removal, although splicing efficiency appears to differ among introns. Excised intron RNAs typically are relatively more abundant in embryos than seedlings. These observations are consistent with a transient imbalance of RNA-processing machinery at the onset of seed germination, which is a period of rapid mitochondrial biogenesis.