Genetics
Transcription Factors Control Snapdragon Asymmetry
By Proceedings of the National Academy of Sciences
Mar 30, 2005, 06:45

RAD, a transcription factor expressed in the dorsal region of a developing snapdragon (Antirrhinum majus), helps coordinate the genes that control the flower's unique asymmetrical shape, according to Susie Corley et al.

Four transcription factors, CYC, DICH, DIV, and RAD, determine the formation of dorsoventral asymmetry in the snapdragon, but how they interact is unclear.

Corley et al. cloned RAD and looked for its expression in the developing flowers of both wild-type and mutant plants. The authors found that RAD encodes a small protein with a MYB-like domain, and is thus a member of one of the largest transcription factor families in plants.

RAD was activated in the dorsal region of developing flowers by CYC and DICH, and once activated, RAD antagonized DIV, preventing its activity in the dorsal regions. DIV produces a transcription factor that leads to petals with ventral characteristics. RAD transcription factor is similar in sequence to the N-terminal domain of DIV, also a MYB transcription factor.

This similarity suggests that the two transcription factors compete for binding sites on DNA or interacting proteins. The authors suggest that RAD evolved from DIV or a common precursor via C-terminal deletion.

All rights reserved by www.rxpgnews.com