A plausible interpretation of pRb2/P130-mediated ER-α transcription regulation in human breast cancer MCF-7 cell line. The upper part of the panel shows a permissive configuration for ER-α transcription, in which a multi-molecular complex comprising pRb2/p130, HDAC1, SUV39H1 and HAT interacts with the ER-α promoter. The lower part of the panel shows a non-permissive configuration for ER-α transcription. In this case, DNMT1 is present in the multi-molecular complex, whereas HAT is released. Abbreviations: HDAC1 = histone deacetylase 1; DNMT1 = DNA (cytosine-5) methyltransferase 1; HAT = histone acetyltransferase; SUV39H1 = histone methyltransferase; TAFs = transcription activating factors; RNA pol II = RNA polymerase II; TBP = TATA binding protein. Transcription factors are reported as: IIA, IIB, IIF, IIH and IIE.