TY - JOUR
T1 - Mutagenesis of Apobec-1 Complementation Factor Reveals Distinct Domains That Modulate RNA Binding, Protein-Protein Interaction with Apobec-1, and Complementation of C to U RNA-editing Activity
AU - Blanc, Valerie
AU - Henderson, Jeffrey O.
AU - Kennedy, Susan
AU - Davidson, Nicholas O.
PY - 2001/12/7
Y1 - 2001/12/7
N2 - C to U editing of apolipoprotein B (apoB) RNA requires a multicomponent holoenzyme complex in which minimal constituents include apobec-1 and apobec-1 complementation factor (ACF). We have examined the predicted functional domains in ACF in binding apoB RNA, interaction with apobec-1, and complementation of RNA editing. We demonstrate that apoB RNA binding and apobec-1-interacting domains are defined by two partially overlapping regions containing the NH 2-terminal RNA recognition motifs of ACF. Both apoB RNA binding and apobec-1 interaction are required for editing complementation activity. ACF is a nuclear protein that upon cotransfection with apobec-1 results in nuclear colocalization and redistribution of apobec-1 from the cytoplasm. ACF constructs with deletions or mutations in the putative nuclear localization signal (NLS) still localize in the nucleus of transfected cells but do not colocalize with apobec-1, the latter remaining pre-dominantly cytoplasmic. These observations suggest that the putative NLS motif in ACF is not responsible for its nucleo-cytoplasmic trafficking. By contrast, protein-protein interaction is important for the nuclear import of apobec-1. Taken together, these data suggest that functional complementation of C to U RNA editing by apobec-1 involves the NH2-terminal 380 residues of ACF.
AB - C to U editing of apolipoprotein B (apoB) RNA requires a multicomponent holoenzyme complex in which minimal constituents include apobec-1 and apobec-1 complementation factor (ACF). We have examined the predicted functional domains in ACF in binding apoB RNA, interaction with apobec-1, and complementation of RNA editing. We demonstrate that apoB RNA binding and apobec-1-interacting domains are defined by two partially overlapping regions containing the NH 2-terminal RNA recognition motifs of ACF. Both apoB RNA binding and apobec-1 interaction are required for editing complementation activity. ACF is a nuclear protein that upon cotransfection with apobec-1 results in nuclear colocalization and redistribution of apobec-1 from the cytoplasm. ACF constructs with deletions or mutations in the putative nuclear localization signal (NLS) still localize in the nucleus of transfected cells but do not colocalize with apobec-1, the latter remaining pre-dominantly cytoplasmic. These observations suggest that the putative NLS motif in ACF is not responsible for its nucleo-cytoplasmic trafficking. By contrast, protein-protein interaction is important for the nuclear import of apobec-1. Taken together, these data suggest that functional complementation of C to U RNA editing by apobec-1 involves the NH2-terminal 380 residues of ACF.
UR - http://www.scopus.com/inward/record.url?scp=0035824516&partnerID=8YFLogxK
U2 - 10.1074/jbc.M107654200
DO - 10.1074/jbc.M107654200
M3 - Article
C2 - 11571303
AN - SCOPUS:0035824516
SN - 0021-9258
VL - 276
SP - 46386
EP - 46393
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 49
ER -