In addition to being effected by many environmental factors, the expression levels of antho-cyanins biosynthetic genes are also modulate by transcription factors (TFs), such as ELONGATED HYPOCOTYL 5 (HY5), basic helix-loop-helix (bhlh) and v-myb avian myeloblastosis viral oncogene homologue (MYB) , which bind to structural gene promoters to modulate gene expression