Fig. 7. Deletion of the N-terminal A/B region of ERα generates a receptor whose transcriptional responses are similar in magnitude to the responses obtained with ERβ. (A) In vitro chromatin assembly and transcription assays comparing the transcriptional activities of ERα, ERβ and ERαΔAB. The assays were performed as described for Figure 1C. The ER proteins, E₂ and TSA were added as indicated. Note that the exposure time for the ‘non-chromatin’ gel was reduced relative to the other two gels to show better the effects on basal transcription. (B) Targeted histone acetylation assays comparing the activities of ERα and ERαΔAB. The assays were performed as described for Figure 5C. Similar assays comparing the activities of ERα and ERβ can be found in Figure 5C.