Two-hybrid cloning identifies an RNA-binding protein, GRY-RBP, as a component of apobec-1 editosome

Biochem Biophys Res Commun. 2001 Apr 13;282(4):977-83. doi: 10.1006/bbrc.2001.4679.


ApoB mRNA editing is mediated by an editosome complex with apobec-1 as its catalytic component. By yeast two-hybrid cloning using apobec-1 as bait we identified a 69.6-kDa RNA binding protein, GRY-RBP, that contains 3 RNA-recognition motifs (RRMs) as a novel apobec-1 associating protein. GRY-RBP may be an alternatively spliced species of NASP1, a protein of known function. GRY-RBP was shown to bind to apobec-1, the catalytic component of apoB mRNA editosome, in vivo and in vitro. Immunodepletion using a monospecific rabbit antibody abolished editing in apobec-1 expressing HepG2 S-100 extracts. GRY-RBD interacted with apobec-1 through its C-terminus. It contains three RRM (RNA recognition motifs) domains that are homologous to those found in human ACF (apobec-1 complementation factor). Phylogeny analysis of the RRM domain-containing proteins indicates that GRY-RBP clusters with hnRNP-R, ACF, and ABBP-1 (another apobec-1 binding protein). In addition to its involvement with apobec-1 editosome, the suggested cellular functions of GRY-RBD and its structural homologues include RNA transport and RNA secondary structure stabilization.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • APOBEC-1 Deaminase
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Antibodies / immunology
  • Cloning, Molecular
  • Cytidine Deaminase / metabolism*
  • Heterogeneous-Nuclear Ribonucleoproteins*
  • Humans
  • Macromolecular Substances
  • Molecular Sequence Data
  • Phylogeny
  • Protein Structure, Tertiary
  • RNA Editing*
  • RNA, Messenger / biosynthesis
  • RNA-Binding Proteins / biosynthesis
  • RNA-Binding Proteins / genetics*
  • RNA-Binding Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Tissue Distribution
  • Tumor Cells, Cultured
  • Two-Hybrid System Techniques*


  • Antibodies
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Macromolecular Substances
  • RNA, Messenger
  • RNA-Binding Proteins
  • SYNCRIP protein, human
  • AICDA (activation-induced cytidine deaminase)
  • APOBEC-1 Deaminase
  • APOBEC1 protein, human
  • Cytidine Deaminase

Associated data

  • GENBANK/AF037448
  • GENBANK/AF093821