Anti-BRD7 monoclonal antibody Made to order

The centrosome associated protein Ceap-16 (also termed BLOS2) can accelerate the proliferation of mouse fibroblast NIH3T3 cells, which mechanism remains unclear. Here we identified tumor suppressor candidate BRD7 (bromodomain containing protein 7), which could negatively regulate cell proliferation and growth, as a novel Ceap-16-interacting protein. Ceap-16 and BRD7 interacted with each other both in vitro and in vivo. The C-terminus of BRD7 and the central region of Ceap-16 mediated the interaction. Through this binding, Ceap-16 could translocate from cytoplasm to the nucleus where it selectively inhibited the transcriptional suppression activity of BRD7 towards certain target genes including E2F3 and cyclin A. Moreover, Ceap-16, BRD7 and historic H3/H4 could form a complex and Ceap-16 did not compete with BRD7 binding to histories. These findings suggest a novel function for Ceap-16 in the transcriptional regulation through associating with BRD7. (C) 2008 Elsevier Inc. All rights reserved.

We carried out a yeast two-hybrid screen using a BRCA1 bait composed of amino acids 1 to 1142 and identified BRD7 as a novel binding partner of BRCA1. This interaction was confirmed by coimmunoprecipitation of endogenous BRCA1 and BRD7 in T47D and HEK-293 cells. BRD7 is a bromodomain containing protein, which is a subunit of PBAF-specific Swi/Snf chromatin remodeling complexes. To determine the functional consequences of the BRCA1-BRD7 interaction, we investigated the role of BRD7 in BRCA1-dependent transcription using microarray-based expression profiling. We found that a variety of targets were coordinately regulated by BRCA1 and BRD7, such as estrogen receptor a (ER alpha). Depletion of BRD7 or BRCA1 in either T47D or MCF7 cells resulted in loss of expression of ERa at both the mRNA and protein level, and this loss of ERa was reflected in resistance to the antiestrogen drug fulvestrant. We show that BRD7 is present, along with BRCA1 and Oct-1, on the ESR1 promoter (the gene which encodes ER alpha). Depletion of BRD7 prevented the recruitment of BRCA1 and Oct-1 to the ESR1 promoter; however, it had no effect on the recruitment of the other Swi/Snf subunits BRG1, BAF155, and BAF57 or on RNA polymerase II recruitment. These results support a model whereby the regulation of ER alpha transcription by BRD7 is mediated by its recruitment of BRCA1 and Oct-1 to the ESR1 promoter. Cancer Res; 70(6); 2538-47. (C)2010 AACR.