UNDERSTANDING THE FUNCTION OF KDAC1 IN ACTIVATION OF GENES BY THE GLUCOCORTICOID RECEPTOR: POTENTIAL ROLES OF THE CoREST COMPLEX

Abstract

The glucocorticoid receptor cooperates with lysine deacetylase-containing complexes to effect transcription of its target genes. One of these complexes, CoREST, has traditionally been thought to have repressive effects on transcription, however, recent evidence shows that particular CoREST complexes facilitate glucocorticoid-activated transcription at select target genes. Scaffold proteins within CoREST are a family of three homologs: Rcor1-3. Only RCOR3-containing CoREST complexes promote glucocorticoid-activated transcription. Study of Rcor3, unlike Rcor1 and 2, is hampered by a lack of commercially-available antibodies. This study focused on developing a tagged version of Rcor3 in a murine hepatoma cell line such that the pro- tein can be isolated and studied with epitope tag-specific antibodies. Our results show that the tagged protein, Rcor3-FLAG, is able to be isolated using ddk and FLAG-M2 antibodies. We also demonstrate that Rcor3-FLAG is able to complex with enzymatically active members of the CoREST complex such as lysine deacetylases and lysine demethylases. Finally, we conclude that Rcor3 is a nuclear protein. Our cellular model of Rcor3 will allow us to further understand which specific GR target genes are activated by CoREST and, overall, provide a mechanism to understand a critical process in physiology- epigenetic regulatory mechanisms involved in glucocorticoid receptor signaling.