ER-RAR Yin and Yang (image) University of Chicago Medical Center Caption This is an artistic depiction of the proposed competitive binding of Retinoic Acid Receptors (blue) and Estrogen Receptor alpha (purple) to a genomic target site to achieve the antagonistic transcriptional effects indicated by the yin and yang symbol. Credit Artwork by Janet Iwasa for the University of Chicago. Usage Restrictions None 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.