Visualization of RNA-protein interactions in living cells: FMRP and IMP1 interact on mRNAs.
Protein expression depends significantly on the stability, translation efficiency and localization of mRNA. These qualities are largely dictated by the RNA-binding proteins associated with an mRNA. Here, we report a method to visualize and localize RNA-protein interactions in living mammalian cells. Using this method, we found that the fragile X mental retardation protein (FMRP) isoform 18 and the human zipcode-binding protein 1 ortholog IMP1, an RNA transport factor, were present on common mRNAs. These interactions occurred predominantly in the cytoplasm, in granular structures. In addition, FMRP and IMP1 interacted independently of RNA. Tethering of FMRP to an mRNA caused IMP1 to be recruited to the same mRNA and resulted in granule formation. The intimate association of FMRP and IMP1 suggests a link between mRNA transport and translational repression in mammalian cells.
Biochemistry Department, University of Otago, Dunedin, New Zealand.
Oliver
O
Rackham
Chris M
CM
Brown
D000199:Actins / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins; D051860:Fragile X Messenger Ribonucleoprotein 1; D006801:Humans; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*
D000199:Actins; D003598:Cytoskeletal Proteins; D051860:Fragile X Messenger Ribonucleoprotein 1; D046912:Multiprotein Complexes; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C497683:FMR1 protein, human; C406144:IGF2BP1 protein, human; C492185:STAU1 protein, human