Apolipoprotein B mRNA Editing Enzyme Catalytic Polypeptide 1 (APOBEC1)

APOBEC1 encodes a member of the cytidine deaminase enzyme family. The encoded protein forms a multiple-protein editing holoenzyme with APOBEC1 complementation factor (ACF) and APOBEC1 stimulating protein (ASP). This holoenzyme is involved in the editing of C-to-U nucleotide bases in apolipoprotein B and neurofibromatosis-1 mRNAs.

This alternative splicing causes a frameshift that produces a novel 36-amino acid peptide. The exon 2-skipped form accounts for approximately 50% of mRNA in the adult small intestine and up to 90% of APOBEC1 mRNA in the developing gut. An antipeptide antibody identified the truncated protein in the villus cells of the adult small intestine.