<Li> 1.2. 2 Family: Myogenic transcription factors (MyoD) </Li> <Li> 1.2. 3 Family: Achaete - Scute </Li> <Li> 1.2. 4 Family: Tal / Twist / Atonal / Hen </Li> <Li> 1.3 Class: Helix - loop - helix / leucine zipper factors (bHLH - ZIP) <Ul> <Li> 1.3. 1 Family: Ubiquitous bHLH - ZIP factors; includes USF (USF1, USF2); SREBP (SREBP) </Li> <Li> 1.3. 2 Family: Cell - cycle controlling factors; includes c - Myc </Li> </Ul> </Li>

In eukaryotes different groups of proteins regulate transcription initiation