Identification of RBM46 as A Novel APOBEC1 Cofactor for C-to-U RNA-Editing Activity

Cytidine (C) to Uridine (U) RNA editing is a post -transcription modification that is involved in diverse biological processes. APOBEC1 (A1) catalyzes the conversion of C -to -U in RNA, which is important in regulating cholesterol metabolism through its editing activity on ApoB mRNA. However, A1 requires a cofactor to form an "editosome" for RNA editing activity. A1CF and RBM47, both RNA -binding proteins, have been identified as cofactors that pair with A1 to form editosomes and edit ApoB mRNA and other cellular RNAs. SYNCRIP is another RNA -binding protein that has been reported as a potential regulator of A1, although it is not directly involved in A1 RNA editing activity. Here, we describe the identification and characterization of a novel cofactor, RBM46 (RNA -Binding -Motif -protein -46), that can facilitate A1 to perform C -to -U editing on ApoB mRNA. Additionally, using the low -error circular RNA sequencing technique, we identified novel cellular RNA targets for the A1/RBM46 editosome. Our findings provide further insight into the complex regulatory network of RNA editing and the potential new function of A1 with its cofactors. (c) 2023 Elsevier Ltd. All rights reserved.