Developmental role of a coactivator MBF1
During gene activation, coactivators mediate the effect of DNA-binding transcription factors to RNA polymerase. Although coactivators are important for transcription, their in vivo roles are poorly understood. We show that an evolutionarily conserved but unique coactivator MBF1 cooperates with a bZIP transcription factor TDF (Tracheae defective) during the formation of the tracheal and nervous systems.
During gene activation, coactivators mediate the effect of DNA-binding transcription factors to RNA polymerase. Although coactivators are important for transcription, their in vivo roles are poorly understood. We show that an evolutionarily conserved but unique coactivator MBF1 cooperates with a bZIP transcription factor TDF (Tracheae defective) during the formation of the tracheal and nervous systems. MBF1 acts by bridging between TDF and the TATA-box binding protein (TBP). Transcription of a TDF-dependent reporter gene is reduced by 80% in mbf1 null mutant embryos. A recessive tdf allele becomes haploinsufficient in the mbf1-deficient embryos, causing severe lesions in the tracheal and central nervous systems. These data are the first genetic analysis of MBF1 function in a multicellular organism and demonstrate its crucial role in organogenesis. (Liu et al., Development 2003).
