CCAAT/enhancer binding protein beta (C/EBPβ) mRNA is translated into multiple protein isoforms. Schematic representation of C/EBPβ mRNA, its three potential translation start sites and the resultant protein isoforms. The transactivation domain, the DNA binding domain (DNA) and the leucine zipper, dimerization domain (Zipper) are indicated. It has been suggested that the upstream open reading frame (uORF) is located within a stem loop structure, and the LAP translation start sites are shown positioned on either side of the uORF. Alternative isoforms, in addition to those represented in this figure, may be present in other tissues and species. LAP, liver-enriched activating protein; LIP, liver-enriched inhibitory protein; UTR, untranslated region.