Replication initiator DnaA interacts with an anti-terminator NusG in T. tengcongensis

DnaA plays a central role in initiation of DNA replication at oriC in bacteria, and is also a transcription regulator which interacts with the DnaA box relative to a specific gene. Through screening the interaction between TtDnaA and the transcription machinery in Thermoanaerobacter tengcongensis by yeast two-hybrid assays, we found for the first time that the TtDnaA could interact with an anti-terminator, TtNusG2, in this thermophilic bacterium. The direct interaction between TtDnaA and TtNusG2 was verified by surface plasmon resonance (SPR) assay in vitro, and was further confirmed by co-immunoprecipitation assay in vivo. Moreover, we demonstrated that domain I and domain III of TtDnaA were responsible for the interaction with TtNusG2. These findings might expand our understanding of cooperation of two fundamental processes, replication and transcription, in this bacterium.