Cipollina Chiara, van den Brink Joost, Daran-Lapujade Pascale, Pronk Jack T, Porro Danilo, de Winde Johannes H
Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, P.za della Scienza 2, 20126 Milano, Italy.
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Microbiology (Reading). 2008 Jun;154(Pt 6):1686-1699. doi: 10.1099/mic.0.2008/017392-0.
Saccharomyces cerevisiae SFP1 is required for nutrient-dependent regulation of ribosome biogenesis and cell size. A mutant deleted for SFP1 shows specific traits, including a slow growth phenotype, especially when growing on glucose. We recently analysed the physiology of an sfp1Delta mutant and its isogenic reference strain in chemostat cultures. This approach was successful in revealing the effects of nutrients on the activity of Sfp1 independent of growth rate-related feedback. In the present work we exposed carbon-limited cultures of an sfp1Delta mutant and its reference strain to sudden glucose excess. This allowed us to study the effect of SFP1 deletion on cell physiology when the cells are forced to exploit their maximum growth potential; this is similar to what happens in shake-flask cultures but with no bias due to growth rate differences. We show that nutrients differentially affect the role of Sfp1 in cell-size modulation and in transcriptional control. Furthermore, we report that while Sfp1 is necessary for the efficient glucose-dependent regulation of ribosome biogenesis genes, it is not required for the proper induction of ribosomal protein genes in response to glucose excess. Finally, our data suggest a role for Sfp1 in the regulation of glycolysis, further underlining its involvement in the network that links ribosome biogenesis and cell metabolism.
酿酒酵母的SFP1是营养依赖型核糖体生物合成调控和细胞大小调控所必需的。缺失SFP1的突变体表现出特定的性状，包括生长缓慢的表型，尤其是在以葡萄糖为碳源生长时。我们最近分析了恒化器培养中sfp1Delta突变体及其同基因参照菌株的生理学特性。这种方法成功地揭示了营养物质对Sfp1活性的影响，而不受生长速率相关反馈的影响。在本研究中，我们将sfp1Delta突变体及其参照菌株的碳限制培养物暴露于突然的葡萄糖过量环境中。这使我们能够研究SFP1缺失对细胞生理学的影响，此时细胞被迫发挥其最大生长潜力；这类似于摇瓶培养中的情况，但不存在生长速率差异导致的偏差。我们发现，营养物质对Sfp1在细胞大小调节和转录控制中的作用有不同影响。此外，我们报告，虽然Sfp1是核糖体生物合成基因有效葡萄糖依赖型调控所必需的，但在葡萄糖过量时核糖体蛋白基因的正常诱导并不需要它。最后，我们的数据表明Sfp1在糖酵解调控中发挥作用，进一步强调了它参与连接核糖体生物合成和细胞代谢的网络。
