Characterization of single base substitutions in edited apolipoprotein B transcripts.

Mature RNA transcripts from a single eukaryotic gene may contain different nucleotide sequences, ranging from alternately spliced exons to transcripts from separate alleles differing by only one base. Our laboratory and others have recently reported another class of RNA sequence differences, occurring in transcripts from the single copy apolipoprotein B (apoB) gene. A unique RNA editing mechanism allows expression of the CAA glutamine codon encoded by the apoB gene at nucleotide 6666, or terminates translation by the introduction of a premature UAA translational stop codon. In this study, we used the polymerase chain reaction (PCR) to amplify and characterize edited apoB RNA transcripts differing by a single nucleotide. Amplification and sequence analysis from small quantities of total RNA will facilitate the study of RNA editing and transcription in general.