Presentation Information
[P03-412]Elucidation of the Physiological Significance of SCO0168 in Streptomyces coelicolor A3(2)
○SOUICHI TOGAWA1, Sota Honma1, Akito Hosoi2, Shinsaku Ito1, Syunnsuke Yajima1, Yasuyuki Sasaki1 (1. Tokyo University of Agriculture Faculty of Life Sciences (Japan), 2. NODAI Genome Research Center,Tokyo university of Agriculture (Japan))
Keywords:
Streptomyces coelicolor,nitric oxide
[Purpose]
Streptomyces coelicolor A3(2) possesses a nitrogen oxide cycle consisting of nitrate, nitrite, and nitric oxide, where NO functions as a signaling molecule regulating secondary metabolism and morphological differentiation. The NO-sensing two-component system DevS/DevR is suggested to directly control genes involved in antibiotic production and development. Our transcriptome analysis revealed that sco0168 expression is markedly decreased in a ΔdevR mutant, and DevR is predicted to bind its promoter. However, the physiological role of SCO0168 remains unclear. This study aimed to elucidate its function.
[Method]
Expression of sco0168 in WT and ΔdevR strains cultured in YEME-Gln medium was analyzed by RT-qPCR. A Δsco0168 mutant was constructed by homologous recombination. Colony size was monitored under four conditions (WT, Δsco0168, with/without 500 µM NaNO2). Actinorhodin (ACT) and undecylprodigiosin (RED) production were quantified. Expression of NO-related genes (hmpA, narG2, devR), antibiotic regulators (actII-ORF4, redD), and neighboring genes (sco0167, sco0169) was analyzed by RT-qPCR.
[Results]
sco0168 expression was significantly reduced in ΔdevR, suggesting positive regulation by DevR. The Δsco0168 strain showed ~66% reduction in colony size compared to WT, and further reduction (~53%) under nitrite conditions, whereas WT was unaffected. Expression of hmpA, narG2, and devR was significantly decreased in Δsco0168. Neighboring genes sco0167 (putative universal stress protein) and sco0169 (putative CBS domain protein) were also downregulated. At 144 h, ACT and RED production markedly increased in Δsco0168 but was suppressed by nitrite. Gene expression analysis showed that actII-ORF4 expression decreased, while redD increased.
[Consideration]
The increased nitrite sensitivity and decreased expression of NO-related genes suggest that deletion of sco0168 impairs the NO cycle and DevS-mediated signaling, thereby disrupting NO homeostasis and reducing devR and narG2 expression.Reduced sco0167 and sco0169 expression imply weakened stress response and energy sensing, which may result in growth defects. Furthermore, although actII-ORF4 expression was reduced, its relationship to ACT production remains unclear, possibly due to a temporal gap between transcription and metabolite accumulation or additional regulatory mechanisms.
[Conclusion]
SCO0168 is suggested to function as a transcriptional regulator involved in NO homeostasis. Taken together, these findings indicate that SCO0168 plays a role in coordinating NO-related gene expression, growth, and antibiotic production in Streptomyces coelicolor.
Streptomyces coelicolor A3(2) possesses a nitrogen oxide cycle consisting of nitrate, nitrite, and nitric oxide, where NO functions as a signaling molecule regulating secondary metabolism and morphological differentiation. The NO-sensing two-component system DevS/DevR is suggested to directly control genes involved in antibiotic production and development. Our transcriptome analysis revealed that sco0168 expression is markedly decreased in a ΔdevR mutant, and DevR is predicted to bind its promoter. However, the physiological role of SCO0168 remains unclear. This study aimed to elucidate its function.
[Method]
Expression of sco0168 in WT and ΔdevR strains cultured in YEME-Gln medium was analyzed by RT-qPCR. A Δsco0168 mutant was constructed by homologous recombination. Colony size was monitored under four conditions (WT, Δsco0168, with/without 500 µM NaNO2). Actinorhodin (ACT) and undecylprodigiosin (RED) production were quantified. Expression of NO-related genes (hmpA, narG2, devR), antibiotic regulators (actII-ORF4, redD), and neighboring genes (sco0167, sco0169) was analyzed by RT-qPCR.
[Results]
sco0168 expression was significantly reduced in ΔdevR, suggesting positive regulation by DevR. The Δsco0168 strain showed ~66% reduction in colony size compared to WT, and further reduction (~53%) under nitrite conditions, whereas WT was unaffected. Expression of hmpA, narG2, and devR was significantly decreased in Δsco0168. Neighboring genes sco0167 (putative universal stress protein) and sco0169 (putative CBS domain protein) were also downregulated. At 144 h, ACT and RED production markedly increased in Δsco0168 but was suppressed by nitrite. Gene expression analysis showed that actII-ORF4 expression decreased, while redD increased.
[Consideration]
The increased nitrite sensitivity and decreased expression of NO-related genes suggest that deletion of sco0168 impairs the NO cycle and DevS-mediated signaling, thereby disrupting NO homeostasis and reducing devR and narG2 expression.Reduced sco0167 and sco0169 expression imply weakened stress response and energy sensing, which may result in growth defects. Furthermore, although actII-ORF4 expression was reduced, its relationship to ACT production remains unclear, possibly due to a temporal gap between transcription and metabolite accumulation or additional regulatory mechanisms.
[Conclusion]
SCO0168 is suggested to function as a transcriptional regulator involved in NO homeostasis. Taken together, these findings indicate that SCO0168 plays a role in coordinating NO-related gene expression, growth, and antibiotic production in Streptomyces coelicolor.
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