APOLIPOPROTEIN-B MESSENGER-RNA EDITING IN-VITRO IS A ZINC-DEPENDENT PROCESS

Apolipoprotein B mRNA editing involves the conversion of a cytidine at nucleotide 6666 to a uridine, thereby creating a translational stop codon from a glutamine codon. Recent evidence suggest that a cytidine deaminase is responsible for catalyzing the C to U conversion. All known nucleotide deaminases require zinc as part of their catalytic domain. Utilizing the selective chelator for zinc, 1,10-penanthroline, we demonstrate that in vitro editing activity in rat liver extracts is zinc dependent. These data, taken together with recent reports, strongly support a role for a cytidine deaminase and nucleotide conversion as the catalytic mechanism for apoB mRNA editing. © 1993 Academic Press, Inc.