The @entity1968 signaling pathway is controlled essentially through two types of nuclear receptors, RARs and RXRs. Ligand dependent activation or repression of @entity554 -regulated genes is dependent on the binding of @entity1968 receptor (RAR)/ @entity8620 receptor ( @entity13351 ) heterodimers to @entity1968 response element (RARE). Although unliganded @entity13351 /RAR heterodimers bind constitutively to DNA in vitro, a clear in vivo ligand-dependent occupancy of the RARE present in the RARbeta2 gene promoter has been reported (Dey, A., Minucci, S., and Ozato, K. (1994) Mol. Cell. Biol. 14, 8191-8201). Nucleosomes are viewed as general repressors of the transcriptional machinery, in part by preventing the access of transcription factors to DNA. The ability of hRXRalpha/hRARalpha heterodimers to bind to a nucleosomal template in vitro has therefore been examined. The assembly of a fragment from the RARbeta2 gene promoter, which contains a canonical DR5 RARE, into a nucleosome core prevented hRXRalpha/hRARalpha binding to this DNA, in conditions where a strong interaction is observed with a linear DNA template. However, histone tails removal by limited proteolysis and histone hyperacetylation yielded nucleosomal RAREs able to bind to hRXRalpha/hRARalpha heterodimers. These data establish therefore the role of histones @entity2733 termini as a major impediment to @entity554 receptors access to DNA, and identify histone hyperacetylation as a potential physiological regulator of @entity554 -induced transcription.

Binding of XXXX receptor heterodimers to DNA. A role for histones @entity2733 termini.

@entity554 :: ('CHEBI:26537', 'Chemical') :: ['retinoid'] @entity2733 :: ('CHEBI:29345', 'Chemical') :: ['NH2'] @entity1968 :: ('MESH:D014212', 'Chemical') :: ['retinoic acid'] @entity13351 :: ('6256', 'Gene') :: ['RXR'] @entity8620 :: ('MESH:C103303', 'Chemical') :: ['9-cis-retinoic acid']
@entity1968 :: (MESH:D014212,Chemical) :: ['retinoic acid']
