[5][6][7] Alternative splicing occurs at this locus and three full-length transcript variants, encoding three distinct isoforms, have been described.

Additional splicing has been observed but the full-length nature of these variants has not been determined.

[7] Mammalian apolipoprotein B mRNA undergoes site-specific C to U deamination, which is mediated by a multi-component enzyme complex containing a minimal core composed of APOBEC1 and a complementation factor encoded by this gene.

[8] The gene product has three non-identical RNA recognition motifs and belongs to the hnRNP R family of RNA-binding proteins.

It has been proposed that this complementation factor functions as an RNA-binding subunit and docks APOBEC1 to deaminate the upstream cytidine.