title: Anti-(Raf-1) RNA aptamers that inhibit Ras-induced Raf-1 activation.
abstract: RNA aptamers with affinity for the Ras-binding domain (RBD) of Raf-1 were isolated from a degenerate pool by in vitro selection. These aptamers efficiently inhibited the Ras interaction with the Raf-1 RBD, and also inhibited Ras-induced Raf-1 activation in a cell-free system. The RNA aptamer with the most potent inhibitory effect specifically inhibited the Ras-Raf-1 interaction and had no affinity for the RBD of the RGL protein, a homolog of the Ral GDP dissociation stimulator. Although the aptamer was capable of binding to the B-Raf RBD, the RNA did not inhibit the interaction between Ras and the B-Raf RBD. Enzymatic and chemical probing experiments indicated that the aptamer was folded into a pseudoknot structure, and some loop regions of the pseudoknot were located at the binding interface for the Raf-1 RBD.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Kimoto
authors.forename: Mikako
authors.initials: M
authors.lastname: Shirouzu
authors.forename: Shin
authors.initials: S
authors.lastname: Mizutani
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Koide
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Kaziro
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hirao
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D019908:Proto-Oncogene Proteins c-raf / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000737:chemistry / Q000494:pharmacology*; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D012313:RNA; D019908:Proto-Oncogene Proteins c-raf; D018631:ras Proteins