GSE32349
Methylation specifies distinct estrogen-induced binding site repertoires of CBP to chromatin (ChIP-Seq)
Multiple signaling pathways ultimately modulate the epigenetic information embedded in the chromatin of gene promoters by recruiting epigenetic enzymes. We found that, in estrogen-regulated gene programming, the acetyltransferase CREB-binding protein (CBP) is specifically and exclusively methylated by the coactivator-associated arginine methyltransferase (CARM1) in vivo. CARM1-dependent CBP methylation and p160 coactivators were required for estrogen-induced recruitment to chromatin targets. Notably, methylation increased the histone acetyltransferase (HAT) activity of CBP and stimulated its autoacetylation. Comparative genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) studies revealed a variety of patterns by which p160, CBP, and methyl-CBP (meCBP) are recruited (or not) by estrogen to chromatin targets. Moreover, significant target gene-specific variation in the recruitment of (1) the p160 RAC3 protein, (2) the fraction of a given meCBP species within the total CBP, and (3) the relative recruitment of different meCBP species suggests the existence of a target gene-specific ''fingerprint'' for coregulator recruitment. Crossing ChIP-seq and transcriptomics profiles revealed the existence of meCBP hubs within the network of estrogen-regulated genes. Together, our data provide evidence for an unprecedented mechanism by which CARM1-dependent CBP methylation results in gene-selective association of estrogen-recruited meCBP species with different HAT activities and specifies distinct target gene hubs, thus diversifying estrogen receptor programming. Overall design: Examination of estrogen-induced binding site in H3396 cells under Estrogen (E2) or Ethanol (EtOH) treatment:  CBP in E2; CBP in EtOH (two technical replicate); CBPR742m in E2 (two technical replicates); CBPR768m in E2; CBPR768m in EtOH; CBPR2151m in E2; CBPR2151m in EtOH; Estrogen receptor alpha (ERa) in E2; ERa in EtOH; Total Histone 3 and 4 acetylated in E2; H3K18ac in E2; H3K18ac in EtOH; Polymerase II (PolII) in E2; PolII in EtOH; RAC3 in E2; Input DNA sample in E2