The Interaction Domain of An Auxin-Related Protein (image) Washington University in St. Louis Share Print E-Mail Caption The transcription factor ARF7 turned out to have a magnet-like interaction region, called a PB1 domain, with positively (blue) and negatively (red) charged faces. Credit Strader, Jez et al. Usage Restrictions please credit Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.