Project description:We report that the winged helix transcription factor FOXA1 is unexpectedly associated with components of single and double stranded-DNA repair complexes. Biochemical studies and high-throughput approaches validated the hierarchical composition of this FOXA1-nucleated machinery and revealed the dependency on FOXA1 for global targeting of the key repair polymerase POLB. Genome-wide DNA methylomes at single-base resolution demonstrated that FOXA1-DNA repair complex is functionally linked to DNA demethylation in a lineage specific fashion. Loss-of-function studies indicate that a significant portion of FOXA1-bound regions display localized reestablishment of methylation and that the subsets with most consistent hypermethylation are represented by active promoters and enhancers that also exhibit the greatest depletion of POLB following FOXA1 removal. Consistently, forced expression of FOXA1 commits its binding sites to an active DNA demethylation in a POLB dependent manner. Finally, we showed that FOXA1-associated DNA demethylation is tightly coupled with genomic targeting of estrogen receptor and estrogen responsiveness. Together, our results link FOXA1-associated DNA demethylation to its transcriptional pioneering.
Project description:We report that the winged helix transcription factor FOXA1 is unexpectedly associated with components of single and double stranded-DNA repair complexes. Biochemical studies and high-throughput approaches validated the hierarchical composition of this FOXA1-nucleated machinery and revealed the dependency on FOXA1 for global targeting of the key repair polymerase POLB. Genome-wide DNA methylomes at single-base resolution demonstrated that FOXA1-DNA repair complex is functionally linked to DNA demethylation in a lineage specific fashion. Loss-of-function studies indicate that a significant portion of FOXA1-bound regions display localized reestablishment of methylation and that the subsets with most consistent hypermethylation are represented by active promoters and enhancers that also exhibit the greatest depletion of POLB following FOXA1 removal. Consistently, forced expression of FOXA1 commits its binding sites to an active DNA demethylation in a POLB dependent manner. Finally, we showed that FOXA1-associated DNA demethylation is tightly coupled with genomic targeting of estrogen receptor and estrogen responsiveness. Together, our results link FOXA1-associated DNA demethylation to its transcriptional pioneering.
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability. genetic_modification_design
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability. ChIP_Seq examination of AR, FoxA1 and GATA2 binding sites in LNCaP and DU145 cells
Project description:It has become clear that DNA repair factors function not only in the maintenance of genomic integrity but also in active DNA demethylation and epigenetic gene regulation. This dual role raises the question if phenotypic abnormalities resulting from deficiency of DNA repair factors are due to DNA damage or impaired DNA demethylation. Here we investigate the bifunctional DNA glycosylases/lyases NEIL1 and NEIL2, which act in repair of oxidative lesions and in epigenetic demethylation.
Project description:Pioneer transcription factors (TFs) exhibit a special ability to bind to and open closed chromatin, facilitating engagement by other regulatory factors involved in gene activation or repression. Chemical probes are lacking for pioneer TFs, which has hindered their mechanistic investigation in cells. Here, we report electrophilic small molecules that stereoselectively and site-specifically bind the pioneer TF, FOXA1, at a cysteine (C258) within the forkhead DNA-binding domain. We show that these covalent ligands react with FOXA1 in a DNA-dependent manner and rapidly remodel its pioneer activity in prostate cancer cells reflected in redistribution of FOXA1 binding across the genome and directionally correlated changes in chromatin accessibility. Motif analysis supports a mechanism where the covalent ligands relax the canonical DNA binding preference of FOXA1 by strengthening interactions with suboptimal ancillary sequences in predicted proximity to C258. Our findings reveal a striking plasticity underpinning the pioneering function of FOXA1 that can be controlled by small molecules.
Project description:Pioneer transcription factors (TFs) exhibit a special ability to bind to and open closed chromatin, facilitating engagement by other regulatory factors involved in gene activation or repression. Chemical probes are lacking for pioneer TFs, which has hindered their mechanistic investigation in cells. Here, we report electrophilic small molecules that stereoselectively and site-specifically bind the pioneer TF, FOXA1, at a cysteine (C258) within the forkhead DNA-binding domain. We show that these covalent ligands react with FOXA1 in a DNA-dependent manner and rapidly remodel its pioneer activity in prostate cancer cells reflected in redistribution of FOXA1 binding across the genome and directionally correlated changes in chromatin accessibility. Motif analysis supports a mechanism where the covalent ligands relax the canonical DNA binding preference of FOXA1 by strengthening interactions with suboptimal ancillary sequences in predicted proximity to C258. Our findings reveal a striking plasticity underpinning the pioneering function of FOXA1 that can be controlled by small molecules.
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability.
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability.
Project description:FoxA1 has been shown critical for prostate development and prostate-specific gene expression regulation. In addition to its well-established role as an AR pioneering factor,several studies have recently revealed significant AR binding events in prostate cancer cells with FoxA1 knockdown. Furthermore, the role of FoxA1 itself in prostate cancer has not been carefully examined. Thus, it is important to understand the role of FoxA1 in prostate cancer and how it interacts with AR signaling. ChIP-Seq examination of AR and FoxA1 binding sites, FAIRE-seq detection of open chromatin genomic regions in DU145 AR +/- FOXA1 cells