Institute for Molecular Biosciences, Goethe University, Biocenter/Max von Laue Straße 9/N200/R3.02, 60438, Frankfurt am Main, Germany.
Frankfurt Institute of Advanced Studies, Frankfurt am Main, Germany.
Plant Cell Rep. 2019 Aug;38(8):937-949. doi: 10.1007/s00299-019-02416-y. Epub 2019 May 13.
Different genes coding for one ribosome biogenesis factor are differentially expressed and are likely under the control of distinct transcription factors, which contributes to the regulatory space for ribosome maturation. Maturation of ribosomes including rRNA processing and modification, rRNA folding and ribosome protein association requires the function of many ribosome biogenesis factors (RBFs). Recent studies document plant-specific variations of the generally conserved process of ribosome biogenesis. For instance, distinct rRNA maturation pathways and intermediates have been identified, the existence of plant specific RBFs has been proposed and several RBFs are encoded by multiple genes. The latter in combination with the discussed ribosome heterogeneity points to a possible function of the different proteins representing one RBF in diversification of ribosomal compositions. Such factor-based regulation would require a differential regulation of their expression, may be even controlled by different transcription factors. We analyzed the expression profiles of genes coding for putative RBFs and transcription factors. Most of the genes coding for RBFs are expressed in a comparable manner, while different genes coding for a single RBF are often differentially expressed. Based on a selected set of genes we document a function of the transcription factors AtMYC1, AtMYC2, AtbHLH105 and AtMYB26 on the regulation of different RBFs. Moreover, on the example of the RBFs LSG1 and BRX1, both encoded by two genes, we give a first hint on a differential transcription factor dependence of expression. Consistent with this observation, the phenotypic analysis of RBF mutants suggests a relation between LSG1-1 and BRX1-1 expression and the transcription factor MYC1. In summary, we propose that the multiple genes coding for one RBF are required to enlarge the regulatory space for ribosome biogenesis.
不同基因编码的一个核糖体生物发生因子的表达水平不同，可能受到不同转录因子的控制，这有助于核糖体成熟的调控空间。核糖体的成熟包括 rRNA 加工和修饰、rRNA 折叠和核糖体蛋白的结合，需要许多核糖体生物发生因子 (RBFs) 的功能。最近的研究记录了植物核糖体生物发生过程中普遍保守的变化。例如，已经确定了不同的 rRNA 成熟途径和中间体，提出了植物特异性 RBFs 的存在，并且几个 RBFs 由多个基因编码。后一种情况与讨论中的核糖体异质性相结合，表明一种 RBF 代表的不同蛋白质可能在核糖体组成的多样化中具有功能。这种基于因子的调节需要对其表达进行差异调节，甚至可能由不同的转录因子控制。我们分析了编码假定 RBF 和转录因子的基因的表达谱。编码 RBF 的大多数基因以相似的方式表达，而单个 RBF 的不同基因通常差异表达。基于一组选定的基因，我们记录了转录因子 AtMYC1、AtMYC2、AtbHLH105 和 AtMYB26 对不同 RBF 调节的功能。此外，以 RBFs LSG1 和 BRX1 为例，它们都由两个基因编码，我们首次暗示了表达的转录因子依赖性差异。与这一观察结果一致，RBF 突变体的表型分析表明 LSG1-1 和 BRX1-1 表达与转录因子 MYC1 之间存在关系。总之，我们提出，一个 RBF 编码的多个基因是扩大核糖体生物发生调控空间所必需的。
