Cloning and characterization of promoter of the mouse mafB gene

The MafB transcription factor plays a pivotal role in controlling the development and differentiation. The author reports the isolation and analysis of genomic clone of the mouse mafB gene. The gene lacks intron structure, at least, within its coding and 5'-untranslated sequences that are similar to the chicken mafB gene. RNA protection analysis determined one transcription initiation site of the gene at 389-bp upstream from the translation initiation site. Sequence analysis showed that the 5'-flanking region upstream to the ATG codon did not contain a conventional TATA box. A TATA-like sequence (5'-GATAAAA-3') and an inverted CCAAT-box (5'-ATTGG-3') were found to be located at nucleotide -31 and -86, referring to the transcription initiation site, respectively. Upstream to these sequences, there were several potential regulatory elements, including two GC-boxes (5'-GGGCGG-3': from -148 to -143; and from -123 to -118), and a palindromic sequence (5'-GTCAGCTGAC-3': from -164 to -155) which contained two halves-MARE (Maf recognition element), 5'-GCTGAC-3', and an E-box (5'-CAGCTG-3'). Promoter activity of the 5'-flanking region was analyzed by reporter transfection assay, which suggested that these segments were an important transcriptional activator. It was also suggested that MyoD transactivated the mouse mafB promoter and this gene was positively autoregulated by its product, MafB.