Two-hybrid cloning identifies an RNA-binding protein, GRY-RBP, as a component of apobec-1 editosome.
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.
Lau
P P
PP
Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Chang
B H
BH
Chan
L
L
D000071479:APOBEC-1 Deaminase; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology; D003001:Cloning, Molecular; D003564:Cytidine Deaminase / Q000378:metabolism*; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017393:RNA Editing; D012333:RNA, Messenger / Q000096:biosynthesis; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
D000906:Antibodies; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D046911:Macromolecular Substances; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C425312:SYNCRIP protein, human; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D000071479:APOBEC-1 Deaminase; C000605089:APOBEC1 protein, human; D003564:Cytidine Deaminase