Assessment of multiple different estrogen receptor-β antibodies for their ability to immunoprecipitate under chromatin immunoprecipitation conditions

摘要

Several different antibodies to total estrogen receptor (ER)β, ERβ1 and ERβ2/cx have been tested and compared for their ability to immunoprecipitate ERβ specific isoforms under chromatin immunoprecipitation conditions (ChIP). The rabbit polyclonal antibodies AP-ERβ1 and AP-ERβ2/cx, specific for ERβ1 and ERβ2/cx isoforms, respectively, were the most efficient for ChIP. The monoclonal antibody MCA1974/PPG5/10 was also able to ChIP ERβ1, but less efficiently than AP-ERβ1. All other antibodies tested were not suitable for ChIP analyses although most antibodies tested immunoprecipitated the appropriate ERβ isoforms under standard conditions. To identify antibodies that can also be used to verify in-vivo expression profiles, a comparison of the antibodies to detect ERβ isoforms by western blotting and immunohistochemistry was also undertaken. Under the tissue processing and autostaining conditions used at the Manitoba Breast Tumor Bank 385P/GC17, MCA1974/PPG5/10, Ab288/14C8 and MCA2279S/57/3 were found to be the best for IHC of ERβ isoforms in human breast tissue biopsy sections, while Ab14021, AP-ERβ1 and AP-ERβ2/cx were best for western blot detection of ERβ isoforms.