Elongation Factor P is important for sporulation initiation

The universally conserved protein Elongation Factor P facilitates translation at amino acids that form peptide bonds with low efficiency, particularly poly-proline tracts. Despite its wide conservation, it is not essential in most bacteria and its physiological role remains unclear. Here, we show that EF-P affects the process of sporulation initiation in the bacterium Bacillus subtilis. We observe that lack of EF-P delays expression of sporulation-specific genes. Using ribosome profiling, we observe that expression of spo0A, encoding a transcription factor that functions as the master regulator of sporulation, is lower in a ∆efp strain as compared to the wildtype. Ectopic expression of Spo0A rescues the sporulation initiation phenotype, indicating that reduced spo0A expression explains the sporulation defect in ∆efp cells. Since Spo0A is the earliest sporulation transcription factor, these data suggest that sporulation initiation can be delayed when protein synthesis is impaired. Ribosome profiling of wild-type B. subtilis and a strain lacking EFP 15 and 60 minutes after induction of sporulation

普遍保守的延伸因子P（Elongation Factor P，EF-P）可促进低效肽键形成氨基酸位点的翻译过程，尤其是多脯氨酸区段。尽管该蛋白具有广泛的保守性，但在大多数细菌中并非必需，其生理功能仍不明确。本研究发现，EF-P可影响枯草芽孢杆菌（Bacillus subtilis）的芽孢形成起始过程。研究观察到，EF-P缺失会延迟芽孢形成特异性基因的表达。通过核糖体谱分析（ribosome profiling），我们发现，相较于野生型菌株，∆efp菌株中编码芽孢形成主调控转录因子的spo0A基因的表达水平更低。异位表达Spo0A可挽救芽孢形成起始缺陷表型，表明spo0A表达下调是∆efp细胞出现芽孢形成缺陷的原因。由于Spo0A是最早的芽孢形成转录因子，上述数据表明，当蛋白质合成受损时，芽孢形成起始过程可被延迟。本研究对芽孢形成诱导后15分钟和60分钟的野生型枯草芽孢杆菌及EFP缺失菌株进行了核糖体谱分析。