Garrido-Godino A I, González R, Martín-Expósito M, Chávez S, Pérez-Ortín J E, Navarro F
Departamento de Biología Experimental-Genética, Universidad de Jaén, campus las Lagunillas, s/n, E-23071 Jaén, Spain.
Instituto de Ciencias de la Vid y del Vino (CSIC-Universidad de La Rioja-Gobierno de La Rioja), Finca La Grajera, Ctra. De Burgos Km. 6, 26007 Logroño, La Rioja, Spain.
Biochim Biophys Acta Gene Regul Mech. 2025 Sep;1868(3):195100. doi: 10.1016/j.bbagrm.2025.195100. Epub 2025 Jun 8.
Cells must adapt to changing environmental conditions to maintain their fitness and to compete with other genotypes during the natural selection process. The growth rate (GR) is a determining factor in this competition, and it influences gene expression. Some genes increase mRNA levels, while others decrease with the GR. mRNA levels depend on the dynamic balance between their synthesis by RNA polymerase II and their degradation rates. RNA polymerase I and III are also influenced by the GR because they transcribe protein synthesis machinery required to make proteins that increase cell mass during growth. Although RNA levels have been extensively studied in relation to the GR in many organisms, synthesis and degradation rates have, however, been much less investigated. In a previous work, we found a positive correlation between RNA polymerase (RNA pol) II transcription and mRNA degradation with GRs in yeast in batch cultures. Here we extend our study under constant growth conditions in a chemostat and find that overall chromatin-associated RNA pol II levels increase in parallel with the GR. This increase appears to involve the accumulation of partially dephosphorylated RNA pol II with a greater tendency to backtracking, which suggests that the GR modifies the phosphorylation state of RNA pol II at the elongation level. RNA pol I also increases its association with chromatin with the GR, which confirms the general dependence of at least RNA pol I and II transcription on the GR.
细胞必须适应不断变化的环境条件，以维持其适应性，并在自然选择过程中与其他基因型竞争。生长速率（GR）是这场竞争中的一个决定性因素，它影响基因表达。一些基因会增加mRNA水平，而另一些则会随着GR而降低。mRNA水平取决于RNA聚合酶II合成与降解速率之间的动态平衡。RNA聚合酶I和III也受到GR的影响，因为它们转录生长过程中增加细胞质量所需蛋白质的蛋白质合成机制。尽管在许多生物体中，RNA水平已被广泛研究与GR的关系，但合成和降解速率的研究却少得多。在之前的一项工作中，我们发现在分批培养的酵母中，RNA聚合酶（RNA pol）II转录与mRNA降解与GR之间存在正相关。在这里，我们在恒化器的恒定生长条件下扩展了我们的研究，发现与染色质相关的总体RNA pol II水平与GR平行增加。这种增加似乎涉及部分去磷酸化的RNA pol II的积累，其回溯倾向更大，这表明GR在延伸水平上改变了RNA pol II的磷酸化状态。RNA pol I也随着GR增加其与染色质的结合，这证实了至少RNA pol I和II转录对GR的普遍依赖性。
