Activates ribosomal RNA transcription, as well other genes. Plays a direct role in upstream activation of rRNA promoters. Binds to a recombinational enhancer sequence that is required to stimulate hin-mediated DNA inversion. Prevents initiation of DNA replication from oriC. Binds to hundreds of transcriptionally active and inactive AT-rich sites, approximately half its binding sites are in non-coding DNA, which only accounts for about 10% of the genome (PubMed:16963779). Homodimer. Scattered throughout the nucleoid (PubMed:21903814). Belongs to the transcriptional regulatory Fis family.