Displaying MYB Family from Sorghum
MYB factors represent a very large and diverse gene family where proteins with two MYB repeats (R2R3, each 50 aa long) are the most common ones, but proteins with just one repeat can be found, too. Each motif consists of three alpha-helices, where the second and third form a helix-turn-helix structure, and the third helix is thought to make contact with the major groove of DNA. Three tryptophan residues in each repeat, spaced by 18-21 aa, form a very conserved cluster among all MYB factors. Compared to the highly conserved MYB domain, other regions in MYB proteins can be highly variable. Today, more than 200 MYB factors are identified in maize (Zea mays) and rice (Oryza sativa) and a comparably high number in other related monocots. Structurally and functionally very diverse MYB factors can be involved in the control of mainly plant specific processes such as plant secondary metabolism, cell morphogenesis or cell fate. Classical MYB factors, which are related to c-Myb, seem to be involved in the control of the cell cycle in animals, plants and other higher eukaryotes.