A retinoic acid-triggered cascade of HOXB1 gene activation.

摘要: Abstract Retinoic acid (RA) has been proposed to be a direct regulator of HOX gene complexes. However, the molecular mechanism RA signaling pathway during normal development is unclear. We have identified an RA-responsive element in promoter HOXB1 composed two functionally separable sites: (i) DR-2 sequence, which target receptor retinoid X heterodimer; and (ii) motif for RA-inducible tissue-specific coactivator termed retinoid-inducible protein. Through neither enhancer alone functional, this combined strongly activates cell-specific retinoid-dependent manner. Finally, activation potentiated by proximal autoregulatory site itself. These data define tripartite cascade leading establishment activation.