BTF2,also named TFⅡH, with multiple subunit complex is believed to have helicase,DNA-dependent ATPase and phosphate kinase activities paticipated in transcription initiation and transcription-coulpled nucleotide-excision repair.During the formation of transcription initiation complex,polymerase ⅡC-terminal domain(CTD),TBP and associated transcription factors are phosphorylated by BTF2/TFⅡH in the presence of TFⅡE.These phosphorylation modifications can be expected to have effects on the regulation of transcription initiation through affecting protein-protein interactions. So BTF2/TFⅡH is an important transcription factor in eukaryotic cells.