CCAAT/enhancer binding protein-β (C/EBP-β), a pivotal regulator of the TATA-less promoter in the rat catalase gene

The rat catalase gene carries a TATA-less promoter and its transcriptional mechanism is interesting because of downregulation in liver injury. We characterized the core element in the promoter and found that C/EBP-β binding downstream of the transcription initiation site plays a crucial role for transcription. The multiple complexes binding to the promoter were composed of homodimers and heterodimers of C/EBP-β isoforms. Transduction of the C/EBP-β gene showed complete reconstitution of multiple binding complexes in HeLa cells, similar to normal liver. Furthermore, C/EBP-β was observed to bind to the endogenous catalase promoter. These data suggest that multiple complex formation of C/EBP-β regulates transcription in the TATA-less catalase promoter.