Kos-Braun Isabelle C, Koš Martin
Biochemistry Center, University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
Microb Cell. 2017 May 1;4(5):179-181. doi: 10.15698/mic2017.05.575.
Most microorganisms are exposed to the constantly and often rapidly changing environment. As such they evolved mechanisms to balance their metabolism and energy expenditure with the resources available to them. When re-sources become scarce or conditions turn out to be unfavourable for growth, cells reduce their metabolism and energy usage to survive. One of the major energy consuming processes in the cell is ribosome biogenesis. Unsurprisingly, cells encountering adverse conditions immediately shut down production of new ribosomes. It is well established that nutrient depletion leads to a rapid repression of transcription of the genes encoding ribosomal proteins, ribosome biogenesis factors as well as ribosomal RNA (rRNA). However, if pre-rRNA processing and ribosome assembly are regulated post-transcriptionally remains largely unclear. We have recently uncovered that the yeast rapidly switches between two alternative pre-rRNA processing pathways depending on the environmental conditions. Our findings reveal a new level of complexity in the regulation of ribosome biogenesis.
大多数微生物都处于不断且常常迅速变化的环境中。因此，它们进化出了一些机制，以便根据自身可利用的资源来平衡其新陈代谢和能量消耗。当资源变得稀缺或条件变得不利于生长时，细胞会降低其新陈代谢和能量使用以存活。细胞中主要的能量消耗过程之一是核糖体生物合成。不出所料，遇到不利条件的细胞会立即停止新核糖体的产生。众所周知，营养物质的消耗会导致编码核糖体蛋白、核糖体生物合成因子以及核糖体RNA（rRNA）的基因转录迅速受到抑制。然而，前体rRNA加工和核糖体组装是否在转录后受到调控在很大程度上仍不清楚。我们最近发现，酵母会根据环境条件在两种替代性的前体rRNA加工途径之间迅速切换。我们的发现揭示了核糖体生物合成调控中一个新的复杂层面。
