RNA aptamers that specifically bind to the Ras-binding domain of Raf-1

RNA aptamers that hind to the Ras-binding domain (RBD) of a proto-oncogene product, Raf-1, were isolated from a pool of random sequences using a glutathione S-transferase-fused RBD (GST-RBD), The RNA molecules bind to the GST-RBD, but not to GST, with dissociation constants of about 300 nM. In contrast, these RNA aptamers do not bind to the Res-binding domain of the RGL protein, which is also known to be activated by Ras, The aptamers actually compete with Ras for binding to the Raf-1 RBD. The anti-Raf-1 aptamers may be used to specifically inhibit the Ras-Raf interaction in the complicated signaling network in mammalian cells. (C) 1998 Federation of European Biochemical Societies.