Project description:Estrogen receptor alpha (ERα) is a ligand dependent transcription regulator, which contains two transactivation functional domains, AF-1 and AF-2. These activities are regulated differently by the ligands. Specifically, the selective estrogen receptor modulators (SERMs) regulate AF-1 rather than AF-2. It is important to know whether AF-1/AF-2 predominantly regulated genes exist in the tissues for a better understanding of the SERMs functionality. We sought out AF-1 dependent estrogenic genes by using the AF-2 mutated knock-in (KI) mouse model, AF2ERKI. AF2ER is an estrogen-insensitive AF-2 disrupted ERα mutant mouse but unique to this model, AF-1 can be activated by the estrogen-antagonist, fulvestrant (ICI), in vitro and in vivo. The information of ICI-mediated gene expression profile of AF2ERKI could define whether AF-1/AF-2 predominantly regulated genes exist in the tissues.
Project description:Estrogen receptor alpha (ERα) is a ligand dependent transcription regulator, which contains two transactivation functional domains, AF-1 and AF-2. These activities are regulated differently by the ligands. Specifically, the selective estrogen receptor modulators (SERMs) regulate AF-1 rather than AF-2. It is important to know whether AF-1/AF-2 predominantly regulated genes exist in the tissues for a better understanding of the SERMs functionality. We sought out AF-1 dependent estrogenic genes by using the AF-2 mutated knock-in (KI) mouse model, AF2ERKI. AF2ER is an estrogen-insensitive AF-2 disrupted ERα mutant mouse but unique to this model, AF-1 can be activated by the estrogen-antagonists, such as fulvestrant (ICI) and 4-hydroxytamoxifen (Tam) in vitro and in vivo. The information of genome-wide ICI or Tam dependent AF-2 mutated ERα binding sites could explain the mechanism of the selective estrogenic action of SERMs through AF-1 dependent gene regulation.
Project description:To advance understanding of mechanisms leading to biological and transcriptional endpoints related to estrogen action in the mouse uterus, we have mapped ERα and RNA polymerase II binding sites using chromatin immunoprecipitation (ChIP) followed by sequencing of enriched chromatin fragments (ChIP-seq). In the absence of hormone, 5184 ERα binding sites were apparent in the vehicle treated ovariectomized uterine chromatin, while 17240 were seen one hour after estrogen (E2) treatment, indicating that some sites are occupied by unliganded ERα, and that ERα binding is increased by E2. Approximately 15% of the uterine ERα binding sites were adjacent to (<10 KB) annotated transcription start sites and many sites are found within genes or are found more than 100 KB distal from mapped genes; however, the density (sites per bp) of ERα binding sites is significantly greater adjacent to promoters. An increase in quantity of sites but no significant positional differences were seen between vehicle and E2 treated samples in the overall locations of ERα binding sites either distal from, adjacent to or within genes. Analysis of the PolII data revealed the presence of poised promoter proximal PolII on some highly upregulated genes. Additionally, co-recruitment of PolII and ERα to some distal enhancer regions was observed. A de novo motif analysis of sequences in the ERα bound chromatin confirmed that estrogen response elements (EREs) were significantly enriched. Interestingly, in areas of ERα binding without predicted ERE motifs, homeodomain transcription factor (Hox) binding motifs were significantly enriched. The integration of the ERα and PolII binding sites from our uterine ChIP-seq data with transcriptional responses revealed in our uterine microarrays has the potential to greatly enhance our understanding of mechanisms governing estrogen response in uterine and other estrogen target tissues.
Project description:Estrogen (E2) signaling through its nuclear receptor, estrogen receptor α (ERα) increases insulin-like growth factor 1 (IGF1) in the rodent uterus, which then initiates further signals via the IGF1 receptor (IGF1R). Directly administering IGF1 results in similar biological and transcriptional uterine responses. Our studies using global ERα-null mice demonstrated a loss of uterine biological responses of the uterus to E2 or IGF1 treatment, while maintaining transcriptional responses to IGF1. To address this discrepancy in the need for uterine ERα in mediating the IGF1 transcriptional vs. growth responses, we assessed the IGF1 transcriptional responses in PgrCre+Esr1f/f (called ERαUtcKO) mice, which selectively lack ERα in progesterone receptor (PGR) expressing cells, including all uterine cells, while maintaining ERα expression in other tissues and cells that do not express Pgr. Additionally, we profiled IGF1-induced ERα binding sites in uterine chromatin using ChIP-seq. Herein, we explore the transcriptional and molecular signaling that underlies our findings to refine our understanding of uterine IGF1 signaling and identify ERα-mediated and ERα-independent uterine transcriptional responses. Defining these mechanisms in vivo in whole tissue and animal contexts provides details of nuclear receptor mediated mechanisms that impact biological systems and have potential applicability to reproductive processes of humans, livestock and wildlife.
Project description:Estrogen (E2) signaling through its nuclear receptor, estrogen receptor α (ERα) increases insulin-like growth factor 1 (IGF1) in the rodent uterus, which then initiates further signals via the IGF1 receptor (IGF1R). Directly administering IGF1 results in similar biological and transcriptional uterine responses. Our studies using global ERα-null mice demonstrated a loss of uterine biological responses of the uterus to E2 or IGF1 treatment, while maintaining transcriptional responses to IGF1. To address this discrepancy in the need for uterine ERα in mediating the IGF1 transcriptional vs. growth responses, we assessed the IGF1 transcriptional responses in PgrCre+Esr1f/f (called ERαUtcKO) mice, which selectively lack ERα in progesterone receptor (PGR) expressing cells, including all uterine cells, while maintaining ERα expression in other tissues and cells that do not express Pgr. Additionally, we profiled IGF1-induced ERα binding sites in uterine chromatin using ChIP-seq. Herein, we explore the transcriptional and molecular signaling that underlies our findings to refine our understanding of uterine IGF1 signaling and identify ERα-mediated and ERα-independent uterine transcriptional responses. Defining these mechanisms in vivo in whole tissue and animal contexts provides details of nuclear receptor mediated mechanisms that impact biological systems and have potential applicability to reproductive processes of humans, livestock and wildlife.
Project description:Bisphenol A (BPA) analogs, bisphenol B (BPB) and bisphenol AF (BPAF) have been widely detected in the environment and human products with increasing frequency. However, uterine health risks caused by BPBBisphenol A (BPA) analogs, bisphenol B (BPB) and bisphenol AF (BPAF) have been widely detected in the environment and human products with increasing frequency. However, uterine health risks caused by BPB and BPAF exposure need to be further elucidated. The study aimed to explore whether BPB or BPAF exposure will induce adverse outcomes in uterus. We then performed gene expression profiling using data obtained from mouse uterus exposed to BPB and BPAF at 28 days.
Project description:Abstract. Very little is known regarding how hormonal exposures impact the epigenetic landscape of developing tissues in the context of a whole organism, in contrast to the impact on cultured cells. Here we took a global approach to understanding how neonatal exposure to the xenoestrogen, diethylstilbestrol (DES), alters the uterine epigenome. RNA-seq and ChIP-seq (H3K4me3, H3K27me3, H3K27ac and H3K4me1) were performed on DES-treated and control uteri. The most striking finding was differential association of H3K27ac and H3K4me1 at typical and super-enhancer regions of 79% of altered genes. These peaks overlapped with previously reported estrogen receptor a (ERα) ChIP-seq peaks. Conditional uterine deletion of ERα (Esr1cKO) conferred protection of 88% of altered genes. H3K27ac ChIP-seq on Esr1cKO samples showed that 72% of protected genes had a differential H3K27ac enhancer. These data suggest that DES regulates gene expression in the neonatal mouse uterus by H3K27ac association at ERα binding sites near estrogen-regulated genes.
Project description:Abstract. Very little is known regarding how hormonal exposures impact the epigenetic landscape of developing tissues in the context of a whole organism, in contrast to the impact on cultured cells. Here we took a global approach to understanding how neonatal exposure to the xenoestrogen, diethylstilbestrol (DES), alters the uterine epigenome. RNA-seq and ChIP-seq (H3K4me3, H3K27me3, H3K27ac and H3K4me1) were performed on DES-treated and control uteri. The most striking finding was differential association of H3K27ac and H3K4me1 at typical and super-enhancer regions of 79% of altered genes. These peaks overlapped with previously reported estrogen receptor a (ERα) ChIP-seq peaks. Conditional uterine deletion of ERα (Esr1cKO) conferred protection of 88% of altered genes. H3K27ac ChIP-seq on Esr1cKO samples showed that 72% of protected genes had a differential H3K27ac enhancer. These data suggest that DES regulates gene expression in the neonatal mouse uterus by H3K27ac association at ERα binding sites near estrogen-regulated genes.
Project description:Ctr9, the key scaffold subunit of the human RNA polymerase II (RNAPII) associated factor complex (PAFc), has been demonstrated as a positive regulator of ERα-positive breast cancer progression and ERα-target gene expression. Previously, we found that knockdown of Ctr9 reduces ERα protein stability and decreases the occupancy of ERα and RNAPII at select ERα-target genes. However, the genome-wide regulation of the occupancy of ERα and RNAPII mediated by Ctr9 is still unclear. Here, we determined the genome-wide ERα and RNAPII occupancy in response to estrogen induction and/or Ctr9 knockdown by performing chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq). We found that loss of Ctr9 dramatically decreases the global occupancy of ERα and RNAPII, highlighting the significance of Ctr9 in regulating estrogen signaling in ERα-positive breast cancer cells. Combining this resource with previously published genomic data sets, we identified a unique subset of ERα and Ctr9 target genes, and further delineates the possible independent function of Ctr9 from other subunits in PAFc.