The apolipoprotein B mRNA editing complex performs a multifunctional cycle and suppresses nonsense-mediated decay.
The C to U editing of apolipoprotein B (apoB) mRNA is mediated by a minimal complex composed of an RNA-binding cytidine deaminase (APOBEC1) and a complementing specificity factor (ACF). This editing generates a premature termination codon and a truncated open reading frame. We demonstrate that the APOBEC1-ACF holoenzyme mediates a multifunctional cycle. The atypical APOBEC1 nuclear localization signal is involved in RNA binding and is used to import ACF into the nucleus as cargo. APOBEC1 alone induces nonsense-mediated decay (NMD). The APOBEC1-ACF complex edits and remains associated with the edited RNA to protect it from NMD. The APOBEC1 nuclear export signal is involved in the export of ACF and the edited apoB mRNA together, to the site of translation.
Chester
Ann
A
RNA Editing Group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
Somasekaram
Angelika
A
Tzimina
Maria
M
Jarmuz
Adam
A
Gisbourne
Jane
J
O'Keefe
Raymond
R
Scott
James
J
Navaratnam
Naveenan
N
D000071479:APOBEC-1 Deaminase; D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003564:Cytidine Deaminase / Q000378:metabolism / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D019913:Nuclear Localization Signals; D017393:RNA Editing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D019913:Nuclear Localization Signals; D012333:RNA, Messenger; D000071479:APOBEC-1 Deaminase; C000605089:APOBEC1 protein, human; D003564:Cytidine Deaminase