Multiple genes are transcribed in Hordeum vulgare and Zea mays that carry the DNA binding domain of the myb oncoproteins.

cDNA clones were isolated from tissue specific cDNA libraries of barley and maize using as a probe the cDNA of the maize gene C1, a regulator of anthocyanin gene expression. C1-related homology for all of the four cDNAs characterized by sequence analysis is restricted to the N-terminal 120 amino acids of the putative proteins. This region shows striking homology to the N-proximal domain of the myb oncoproteins from vertebrates and invertebrates. Within the myb proto-oncogene family this part of the respective gene products functions as a DNA binding domain. Acidic domains are present in the C-proximal protein segments. Conservation of these sequences, together with the genetically defined regulator function of the C1 gene product, suggest that myb-related plant genes code for trans-acting factors which regulate gene expression in a given biosynthetic pathway.