State-dependent promoter switching mediates integrase gene transcription in the integrative and conjugative element ICE Kp1 of Klebsiella pneumoniae

Integrative and conjugative elements (ICEs) are mobile genetic elements that widely disseminate adaptive traits among bacterial populations. Despite their prevalence, the regulatory mechanisms orchestrating ICE integration and excision remain poorly understood. Here, we investigate the transcriptional regulation of the integrase gene (int) in ICEKp1 of Klebsiella pneumoniae. Our results demonstrate that the integrated ICEKp1 exploits the adjacent host transfer RNA-asn promoter to drive int trans