Regulatory Mechanism Of Archaeal FHA-Domain-Containing Protein

The mechanism and target regulatory genes for Forkhead (FHA) domain-containing transcriptional factor have not yet been documented in Archaea, the third domain of life. In this study, using a bacterial one-hybrid technique, we successfully screened and identified for the first time a target gene regulated by ST0829, a FHA domain-containing potential transcriptional factor, containing an N-terminal Zn finger-RanBP domain, in the hyperthermophilic archaeon Sulfolobus tokodaii. We mainly obtained several results as following:(1) We constructed a S. tokodaii str.7 promoter library. (2) Using bacteria one-hybridization assay, an archaea flagellar protein operon (FlaG, FlaF, FlaH, FlaI and FlaJ) was found to be potentially regulated by ST0829. (3) ST0829 could specifically bind to the promoter of archaea flagellar protein operon by experiment both in vitro and in vivo, such as EMSA, SPR, and CHIP. (4) When phosphorylated by ST1565 protein, ST0829 had a significantly reduced DNA-binding activity. (5) Protein ST0829 could interact with the RNA polymeraseβsubunit, and presented self-regulation mechanism.We successfully characterized the first target gene promoter for archaeal FHA domain containing regulator and confirmed the specific binding between the transcriptional factor and target DNA sequence both in vitro and in vivo experiments. These date not only increase our knowledge of function of archaeal FHA-domain-containing protein but also offer important information for further understanding the signaling mechanism of environmental adaptation in archaea.