A phage-derived promoter SD13 enables strong and cross-host gene expression in Streptomyces and Escherichia coli
摘要
Efficient and tunable promoters are essential tools for metabolic engineering and synthetic biology in Streptomyces. In this study, the lytic bacteriophage phiSASD1 was exploited as a source of novel regulatory elements. Fifteen candidate promoter fragments were identified through bioinformatic prediction and systematically evaluated using a catechol 2,3-dioxygenase (xylE) reporter system in Streptomyces lividans TK54 and Escherichia coli JM109. Among these candidates, seven fragments exhibited measurable promoter activity, with PSD13 showing the highest transcriptional strength. In S. lividans, PSD13 displayed up to a 9.79-fold higher activity than the widely used strong promoter PermE*, while retaining detectable activity in E. coli, indicating excellent cross-host compatibility. Sequence analysis combined with 5′ RACE revealed that PSD13 possesses a typical σ⁷⁰-dependent promoter architecture, with its core functional region located between − 70 to + 9 bp relative to the transcription start site. Furthermore, PSD13 efficiently drove the soluble expression of phage endolysin in E. coli, potentially reducing inclusion body formation compared with conventional T7-based expression systems. Collectively, these results identify PSD13 as a phage-derived promoter exhibiting strong activity in both Streptomyces and E. coli, suggesting its potential as a useful genetic element for Streptomyces engineering and heterologous gene expression.
• Strong transcriptional promoters were systematically identified from Streptomyces phages.
• The novel SD13 promoter shows higher activity than PermE* and works across hosts.
• SD13 promoter efficiently expresses soluble heterologous proteins, advancing Streptomyces synthetic biology.