Far Upstream Element Binding Protein 3 (FUBP3)

The far upstream element (FUSE)-binding protein FBP1 (FUBP1) binds to the FUSE of the human MYC protooncogene. Davis-Smyth et al. (1996) isolated cDNAs encoding FBP2 (KHSRP) and FBP3. Like FBP1 and FBP2, the predicted 600-amino acid FBP3 protein contains 3 distinct domains.

The central nucleic acid-binding region contains 4 regularly spaced alternating units, each consisting of a KH motif and an amphipathic helix. Expression studies in mammalian cells indicated that the C-terminal domains of the FBPs are potent transcriptional activators. The FBPs bound specifically to 1 strand of the FUSE in vitro. Northern blot analysis revealed that FBP3 was expressed as a 3.4-kb mRNA in all cells and tissues tested.