Sequence logos for (A) PAC, (B) mRRPE, (C) mRRSE10, and (D) mRRSE10, produced with the World Wide Web service athttp://www.bio.cam.ac.uk/cgi-bin/seqlogo/logo.cgi. The height of each letter is proportional to its frequency of occurrence in the binding site matrix times the information content at each position.