RAR-β4, a retinoic acid receptor isoform is generated from RAR-β2 by alternative splicing and usage of a CUG initiator codon

Abstract

An isoform of retinoic acid receptor β, RAR-β4, has been identified. RAR-β4 is expressed under the control of the same retinoic acid-responsive promoter as RAR-β2. RAR-β4, which is generated by alternative splicing from the same primary transcripts as RAR-β2, is initiated by a non-AUG codon, CUG. The amino acid sequence of RAR-β4 in regions B-F is identical to that of the other RAR-β isoforms β1, β2, and β3. However, the RAR-β4 A region is much shorter (4 amino acids long) than those of these isoforms. RAR-β4 exhibits a tissue-specific pattern of expression and distinct transcriptional activation properties when compared with the other RAR-β isoforms.