Core Recognition Element (IMAGE) Rutgers University Caption A crystal structure of a functional, promoter-dependent transcription initiation complex reveals that RNA polymerase core enzyme makes sequence-specific interactions with single-stranded DNA in the promoter -4/+2 region ("core recognition element," CRE). The interactions include the unstacking of the +2 base and its insertion into a deep pocket (cyan box). [RNA polymerase core enzyme is in gray. Bases of the CRE are numbered in pink. Downstream double-stranded DNA is seen end-on.] Credit Yu Zhang and Richard H. Ebright, Rutgers University Usage Restrictions Permission is granted to reproduce the image in connection with news coverage of this story. All other rights are reserved. License Licensed content 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.