GRSF-1: a poly(A)+ mRNA binding protein which interacts with a conserved G-rich element.
Computer predictions identified similarities to a 14-base G-rich element in numerous mRNAs at a variety of locations. A Northwestern screening strategy was used to obtain a cDNA clone from a HeLa cell library using the G-rich RNA element as a probe. A cellular protein (called GRSF-1), which was encoded by this cDNA, binds RNAs containing the G-rich element. GRSF-1 was distinct from DSEF-1, a nuclear protein we have previously identified that interacts with the G-rich element, based on differences in molecular weight and partial peptide maps, as well as the lack of cross-reactivity with GRSF-1 specific monoclonal antibodies. Using indirect immunofluorescence microscopy, we localized GRSF-1 to the cytoplasm. In vivo UV cross-linking further demonstrated that GRSF-1 was bound to poly(A)+ mRNA in living human cells. Western blot analysis revealed four cytoplasmic proteins which expressed GRSF-1 specific epitopes. GRSF-1 contains three potential RNA recognition motifs and two auxiliary domains. Curiously, the domain organization of GRSF-1 is similar to the RNA binding proteins PUB1, ELAV, HuD, Hel-N1, mcs94-1 and RBP9.
Qian
Z
Z
Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School and Graduate School of Biomedical Sciences, Newark 07103.
Wilusz
J
J
D000595:Amino Acid Sequence; D001482:Base Composition; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004247:DNA; D006147:Guanine / Q000032:analysis; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D039102:Poly(A)-Binding Proteins; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
C088356:GRSF1 protein, human; D039102:Poly(A)-Binding Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D006147:Guanine; D004247:DNA