| A splice variant of the ITF 2 transcript encodes a transcription factor that inhibits MyoD activity . ^^^ ITF 2 is a bHLH protein with widespread expression that is thought to form active heterodimers with MyoD , a muscle specific bHLH transcription factor . ^^^ Thus , differentially spliced transcripts of mouse ITF 2 encode different proteins that appear to dimerize with MyoD and activate or repress transcription . . ^^^ |