21.5 Steroid receptors have ○ severalindependent domains Figure 21. 5 The first finger of cool a steroid receptor controls DNA binding Dimerization specificity of DNA-binding (positions shown in red); the second finger controls specificity of dimerization (positions shown in blue). The expanded view of the first finger shows that 回 discrimination between GRE ■■■■■ 少 Glucocorticoid Estrogen and ere target sequences rests speciFIcIty specificity on two amino acids at the base O Same sequence in both receptors O Different sequence in each receptor 请莘大
Figure 21.5 The first finger of a steroid receptor controls specificity of DNA-binding (positions shown in red); the second finger controls specificity of dimerization (positions shown in blue). The expanded view of the first finger shows that discrimination between GRE and ERE target sequences rests on two amino acids at the base. 21.5 Steroid receptors have several independent domains
21.5 Steroid receptors have severalindependent domains Coactivators Basal apparat us Transcription fad or P CAF Figure 21 19 CP日300 Coactivators may have hat 3) activities that Histone tails] acetylate the RNA polym erase, tails of nucleosomal A AC histones a 请莘大
Figure 21.19 Coactivators may have HAT activities that acetylate the tails of nucleosomal histones. 21.5 Steroid receptors have several independent domains
21.5 Steroid receptors have severalindependent domains Sin 3 Corepressor Rpd3 (Acetylase) (DNA-bindin Figure 21.20A repressor complex contains three components: a dNA binding subunit, a corepressor. and a histone deacetylase 请莘大
Figure 21.20 A repressor complex contains three components: a DNA binding subunit, a corepressor, and a histone deacetylase. 21.5 Steroid receptors have several independent domains
Repression in absence of ligand 21.5 Steroid receptors have Corepressor severalindependent domains SMRT Figure 21.9 TR and RAR bind the smrt corepressor toroid receptor in the absence of ligand The promoter is not Ligand triggers activation expressed. When SMRT is displaced by binding of Coactivators VOCAL Basal apparatus ligand, the receptor binds a coactivator complex. This CBP/ p300 TBP leads to activation of transcription by the basa RNA polymerase apparatus udano 请莘大
Figure 21.9 TR and RAR bind the SMRT corepressor in the absence of ligand. The promoter is not expressed. When SMRT is displaced by binding of ligand, the receptor binds a coactivator complex. This leads to activation of transcription by the basal apparatus. 21.5 Steroid receptors have several independent domains