Transcription activator, when associated with MYB75/PAP1 or MYB90/PAP2. Involved in the control of flavonoid pigmentation. Plays a key role in regulating leucoanthocyanidin reductase (BANYULS) and dihydroflavonol-4-reductase (DFR). Not required for leucoanthocyanidin dioxygenase (LDOX) expression. Homodimer (Probable). Interacts with MYB4, MYB5, MYB6, MYB82, MYB113, MYB114, MYB75/PAP1, MYB90/PAP2, and TT2. Buds, flowers and developing siliques, but not in leaves, stems and roots. Faint expression in buds and flowers. Increases during the very early stages of seed development, reaches a maximum at the globular embryo stage and stays high throughout seed formation. TT8 might interact with TT2 and TTG1 to modulate the late genes of the flavonoid pathway. Belongs to the bHLH protein family. Extended C-terminus.