Polyclonal antibodies from rabbits and chickens against the estrogen receptor and related peptides. Use in the affinity isolation of estrogen receptors and the retrieval of chromatin fragments associating with estrogen receptors.

Polyclonal antibodies from chickens and rabbits have been prepared against polypeptides representing two regions of the human estrogen receptor (hER). The estrogen receptor (ER) peptides used as antigens were overproduced in Escherichia coli. When indicated, the antibodies were affinity purified using resins to which the antigens contained in bacterial inclusion bodies had been coupled in high yield to epoxy-activated agarose. The antibodies recognize denatured human, bovine, rat, and rabbit ER in immunoblotting experiments. Immuno-precipitation of native ER protein was readily accomplished using rabbit antisera and immobilized protein A. The chicken antibodies, available in larger quantities, were also useful for immunoisolation after coupling to agarose. With the use of these reagents, the selective retrieval of chromatin fragments from MCF-7 cells that interact with ER has been achieved.