A Novel Zn₂Cys₆ Transcription Factor, TopC, Positively Regulates Trichodin A and Asperpyridone A Biosynthesis in <i>Tolypocladium ophioglossoides</i>

Abstract

Asperpyridone A represents an unusual class of pyridone alkaloids with demonstrated potential for hypoglycemic activity, primarily by promoting glucose consumption in HepG2 cells. Trichodin A, initially isolated from the marine fungus Trichoderma sp. strain MF106, exhibits notable antibiotic activities against Staphylococcus epidermidis. Despite their pharmacological significance, the regulatory mechanisms governing their biosynthesis have remained elusive. In this investigation, we initiated the activation of a latent gene cluster, denoted as “top”, through the overexpression of the Zn2Cys6 transcription factor TopC in Tolypocladium ophioglossoides. The activation of the top cluster led to the biosynthesis of asperpyridone A, pyridoxatin, and trichodin A. Our study also elucidated that the regulator TopC exerts precise control over the biosynthesis of asperpyridone A and trichodin A through the detection of protein–nucleic acid interactions. Moreover, by complementing these findings with gene deletions involving topA and topH, we proposed a comprehensive biosynthesis pathway for asperpyridone A and trichodin A in T. ophioglossoides.

Keywords

• asperpyridone A
• trichodin A
• biosynthesis
• TopC
• <i>Tolypocladium ophioglossoides</i>
• cryptic gene cluster