21.5 Steroid receptors have 8 severalindependent domains ● Figure 21.5 The first finger of 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 02@→@ 2++ discrimination between GRE oh E Glucocorticoid Estrogen and ERE target sequences rests specificity specificity on two amino acids at the base. Same sequence in both receptors Different sequence in each receptor 清菜大当
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 several independent domains Coactivators Basal apparatus Transcription fad or PCAF Figure 21.19 CPB/p300 Coactivators may have HAT )D)) activities that Histone tails acetylate the RN A polym erase tails of nucleosomal histones. 清第大当
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 several independent domains Sin3 (Corepresson Rpd3 Ume (Daecetylase) DNA-binding) Figure 21.20A ))) repressor complex contains three components:a DNA binding subunit,a A corepressor,and a histone deacetylase. 情菜大兰
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 several independent domains SMRT NN\N八N入NN Figure 21.9 TR and RAR bind the SMRT corepressor Steroid receptor in the absence of ligand. The promoter is not Ligand triggers activation expressed.When SMRT is displaced by binding of Coactivators Basal apparatus ligand,the receptor binds a PCAF coactivator complex.This CBP/p300 TBP leads to activation of N入N八NN八N transcription by the basal RNA polymerase apparatus. 清菜大兰
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