Project description:We report the in vivo androgen receptor (AR) binding sites in murine prostate, epididymis and kidney in response to physiological androgen testosterone using ChIP-sequencing and gene expression profiling by microarray. From AR cistrome analysis, we identified tissue-specific collaborating factors i.e. FoxA1 in prostate, Hnf4a in kidney and AP2a in epididymis and validated by ChIP-seq. The ChIP experiments have been performed using antibodies specific to AR, FoxA1, Hnf4a, AP-2a and IgG non-specific antibody as a negative control. Examination of AR binding sites in murine androgen-responsive tissues prostate, epididymis and kidney using ChIP-seq. Further analysis of AR cistromes led to identification of tissue-specific collaborating factors and these collaborating factors are validated by ChIP-seq from the same tissues. Two parallel IgG samples were sequenced, merged together and used as a control data set. Parallel ChIP-seq samples were sequenced and merged for each replicate wherever required to contain approximately the same amount of reads across all tissues and conditions. All ChIP-seq experiments are performed in biological duplicates except for the castrated conditions.
Project description:Tissue-specific transcription factors control the transcriptome through an association with noncoding regulatory regions (cistromes). Identifying the combination of transcription factors that dictate specific cell fate, their specific cistromes and examining their involvement in complex human traits remain a major challenge. Here we focus on the retinal pigmented epithelium (RPE), an essential lineage for retinal development and function and the primary tissue affected in age-related macular degeneration (AMD), a leading cause of blindness. By combining mechanistic findings in stem-cell-derived human RPE, in- vivo functional studies in mice and global transcriptomic and proteomic analyses, we revealed that the key developmental transcription factors LHX2 and OTX2 function together in transcriptional module containing LDB1 and SWI/SNF (BAF) to regulate the RPE transcriptome. Importantly, the intersection between the identified LHX2-OTX2 cistrome with published expression quantitative trait loci, ATAC-seq data from human RPE, and AMD GWAS data, followed by functional validation using a reporter assay, revealed a causal genetic variant that affects AMD risk by altering TRPM1 expression in the RPE through modulation of LHX2 transcriptional activity on its promoter. Taken together, the reported cistrome of LHX2 and OTX2, the identified downstream genes and interacting co-factors reveal the RPE transcription module and uncover a causal regulatory risk SNP in the multifactorial common blinding disease AMD.
Project description:Esophageal squamous cell carcinoma (ESCC) is the sixth leading cause of cancer death worldwide. Emerging evidence suggests that the androgen receptor (AR) is involved in ESCC tumorigenesis. However, how AR exerts its genomic functions in ESCC remains unknown. Here, by defining AR cistromes and analyzing androgen-regulated transcriptomes, we find that AR downregulates the majority of its target genes in ESCC cells. We further find that the pioneer factor GATA3 governs AR-repressed transcription by recruiting SMRT/HDAC3 co-repressors to target gene loci. Importantly, genetic inhibition of GATA3 or pharmacological inhibition of AR/HDAC3 relieves AR-mediated gene repression, leading to ESCC cell growth inhibition in vitro and in vivo. Our findings reveal molecular mechanisms underlying the oncogenomic function of AR in ESCC and identify the GATA3-directed AR transcriptional repression program as a therapeutic target for ESCC.
Project description:The nucleosome is a fundamental unit of chromatin in eukaryotes, and generally prevents the binding of transcription factors to genomic DNA. Pioneer transcription factors overcome the nucleosome barrier, and bind their target DNA sequences in chromatin. OCT4 is a representative pioneer transcription factor that plays a role in stem cell pluripotency. In the present study, we biochemically analyzed the nucleosome binding by OCT4. Crosslinking mass spectrometry showed that OCT4 binds the nucleosome.
Project description:Pioneer transcription factors (TFs) regulate cell fate by establishing transcriptionally primed and active states. However, cell fate control requires the coordination of both lineage-specific gene activation and repression of alternative lineage programs, a process that is poorly understood. Here, we demonstrate that the pioneer TF Forkhead box A (FOXA), required for endoderm lineage commitment, coordinates with the PR domain zinc finger 1 (PRDM1) TF to recruit Polycomb repressive complexes, which establish bivalent enhancers and repress alternative lineage programs. Similarly, the pioneer TF OCT4 coordinates with PRDM14 to repress cell differentiation programs in pluripotent stem cells, suggesting this is a common feature of pioneer TFs. We propose that pioneer and PRDM TFs coordinate recruitment of Polycomb complexes to safeguard cell fate.
Project description:Pioneer transcription factors (TFs) regulate cell fate by establishing transcriptionally primed and active states. However, cell fate control requires the coordination of both lineage-specific gene activation and repression of alternative lineage programs, a process that is poorly understood. Here, we demonstrate that the pioneer TF Forkhead box A (FOXA), required for endoderm lineage commitment, coordinates with the PR domain zinc finger 1 (PRDM1) TF to recruit Polycomb repressive complexes, which establish bivalent enhancers and repress alternative lineage programs. Similarly, the pioneer TF OCT4 coordinates with PRDM14 to repress cell differentiation programs in pluripotent stem cells, suggesting this is a common feature of pioneer TFs. We propose that pioneer and PRDM TFs coordinate recruitment of Polycomb complexes to safeguard cell fate.
Project description:Transcription factors are among the most attractive therapeutic targets but are considered largely undruggable. Here we provide evidence that small molecule-mediated partitioning of the androgen receptor, an oncogenic transcription factor, into phase-separated condensates has therapeutic effect in prostate cancer. We show that the phase separation capacity of the androgen receptor is driven by aromatic residues and short unstable helices in its intrinsically disordered activation domain. Based on this knowledge, we developed tool compounds that covalently attach aromatic moieties to cysteines in the receptors’ activation domain. The compounds enhanced partitioning of the receptor into condensates, facilitated degradation of the receptor, inhibited androgen receptor-dependent transcriptional programs, and had antitumorigenic effect in mouse models of prostate cancer and castration resistant prostate cancer. These results establish a generalizable framework to target the phase-separation capacity of intrinsically disordered regions in oncogenic transcription factors and other disease-associated proteins with therapeutic intent.
Project description:Transcription factors are among the most attractive therapeutic targets but are considered largely undruggable. Here we provide evidence that small molecule-mediated partitioning of the androgen receptor, an oncogenic transcription factor, into phase-separated condensates has therapeutic effect in prostate cancer. We show that the phase separation capacity of the androgen receptor is driven by aromatic residues and short unstable helices in its intrinsically disordered activation domain. Based on this knowledge, we developed tool compounds that covalently attach aromatic moieties to cysteines in the receptors’ activation domain. The compounds enhanced partitioning of the receptor into condensates, facilitated degradation of the receptor, inhibited androgen receptor-dependent transcriptional programs, and had antitumorigenic effect in mouse models of prostate cancer and castration resistant prostate cancer. These results establish a generalizable framework to target the phase-separation capacity of intrinsically disordered regions in oncogenic transcription factors and other disease-associated proteins with therapeutic intent.