Similar Datasets
Project description:Exposure of macrophages to cytokines and pathogen-associated molecular patterns (PAMPs) can alter their subsequent stimulus responses, in part by epigenetic reprogramming. Our previous studies identified dynamic control of NFκB as a specificity mechanism for inducing hundreds of de novo enhancers in murine macrophages. A second set of hundreds of de novo enhancers are associated with the ISRE DNA binding element of the family of interferon regulatory factors (IRFs). In this project, we have dissected the roles of three endotoxin-responsive IRFs in macrophage de novo enhancer formation. While IRF3 was previously hypothesized to be a chromatin remodeling transcription factor, we found that its genetic requirement for enhancer formation (H3K4me1) is indirect, mediated by its role in type I IFN expression which activates the IRF9-containing ISGF3 transcription factor. However, our analysis shows that ISGF3 is unable to trigger enhancer formation on its own – it must cooperate with IRF1. Timecourse analysis of chromatin accessibility by ATAC-seq reveals that IRF1 plays a major role in the early steps of nucleosome eviction, while its partner ISGF3 then reinforces eviction and H3K4me1 deposition on neighboring nucleosomes. Further studies revealed that IRF1 can also cooperate with the type II IFN-induced GAF transcription factor, generating an additional set of IRF1-GAF-specific enhancers. Finally, global gene expression analysis by RNA-seq reveals that these IRF1-dependent enhancers are associated with potentiated expression of nearby genes in response to secondary immune threat exposure. Together our results reveal unexpected combinatorial coordination of IRF transcription factors in epigenomic reprograming to provide innate immune memory in a manner that is restricted to direct pathogen exposure or type II IFN-associated T-cell immunity, but not secondary innate immune stimulation via type I IFN.
2024-02-14 | GSE241818 | GEO
Project description:Exposure of macrophages to cytokines and pathogen-associated molecular patterns (PAMPs) can alter their subsequent stimulus responses, in part by epigenetic reprogramming. Our previous studies identified dynamic control of NFκB as a specificity mechanism for inducing hundreds of de novo enhancers in murine macrophages. A second set of hundreds of de novo enhancers are associated with the ISRE DNA binding element of the family of interferon regulatory factors (IRFs). In this project, we have dissected the roles of three endotoxin-responsive IRFs in macrophage de novo enhancer formation. While IRF3 was previously hypothesized to be a chromatin remodeling transcription factor, we found that its genetic requirement for enhancer formation (H3K4me1) is indirect, mediated by its role in type I IFN expression which activates the IRF9-containing ISGF3 transcription factor. However, our analysis shows that ISGF3 is unable to trigger enhancer formation on its own – it must cooperate with IRF1. Timecourse analysis of chromatin accessibility by ATAC-seq reveals that IRF1 plays a major role in the early steps of nucleosome eviction, while its partner ISGF3 then reinforces eviction and H3K4me1 deposition on neighboring nucleosomes. Further studies revealed that IRF1 can also cooperate with the type II IFN-induced GAF transcription factor, generating an additional set of IRF1-GAF-specific enhancers. Finally, global gene expression analysis by RNA-seq reveals that these IRF1-dependent enhancers are associated with potentiated expression of nearby genes in response to secondary immune threat exposure. Together our results reveal unexpected combinatorial coordination of IRF transcription factors in epigenomic reprograming to provide innate immune memory in a manner that is restricted to direct pathogen exposure or type II IFN-associated T-cell immunity, but not secondary innate immune stimulation via type I IFN.
2024-02-14 | GSE241819 | GEO
Project description:Exposure of macrophages to cytokines and pathogen-associated molecular patterns (PAMPs) can alter their subsequent stimulus responses, in part by epigenetic reprogramming. Our previous studies identified dynamic control of NFκB as a specificity mechanism for inducing hundreds of de novo enhancers in murine macrophages. A second set of hundreds of de novo enhancers are associated with the ISRE DNA binding element of the family of interferon regulatory factors (IRFs). In this project, we have dissected the roles of three endotoxin-responsive IRFs in macrophage de novo enhancer formation. While IRF3 was previously hypothesized to be a chromatin remodeling transcription factor, we found that its genetic requirement for enhancer formation (H3K4me1) is indirect, mediated by its role in type I IFN expression which activates the IRF9-containing ISGF3 transcription factor. However, our analysis shows that ISGF3 is unable to trigger enhancer formation on its own – it must cooperate with IRF1. Timecourse analysis of chromatin accessibility by ATAC-seq reveals that IRF1 plays a major role in the early steps of nucleosome eviction, while its partner ISGF3 then reinforces eviction and H3K4me1 deposition on neighboring nucleosomes. Further studies revealed that IRF1 can also cooperate with the type II IFN-induced GAF transcription factor, generating an additional set of IRF1-GAF-specific enhancers. Finally, global gene expression analysis by RNA-seq reveals that these IRF1-dependent enhancers are associated with potentiated expression of nearby genes in response to secondary immune threat exposure. Together our results reveal unexpected combinatorial coordination of IRF transcription factors in epigenomic reprograming to provide innate immune memory in a manner that is restricted to direct pathogen exposure or type II IFN-associated T-cell immunity, but not secondary innate immune stimulation via type I IFN.
2024-02-14 | GSE241817 | GEO
Project description:IRF1 cooperates with ISGF3 or GAF to form de novo enhancers in murine macrophages
| PRJNA1010180 | ENA
Project description:IRF1 cooperates with ISGF3 or GAF to form de novo enhancers in murine macrophages (RNA-Seq)
| PRJNA1010183 | ENA
Project description:IRF1 cooperates with ISGF3 or GAF to form de novo enhancers in murine macrophages (ChIP-Seq)
| PRJNA1010184 | ENA
Project description:IRF1 cooperates with ISGF3 or GAF to form de novo enhancers in murine macrophages (ATAC-Seq)
| PRJNA1010182 | ENA
Project description:To understand in detail the transcriptional and functional overlap of IFN-I- and IFN-II-activated responses, we used an integrative RNAseq-ChIPseq approach in Huh7.5 cells and characterized the genome-wide role of pSTAT1, pSTAT2, IRF9 and IRF1 in time-dependent ISG expression. For the first time, our results provide detailed insight in the timely steps of IFNα- and IFNγ-induced transcription, in which pSTAT1- and pSTAT2-containing ISGF3 and GAF-like complexes and IRF1 are recruited to individual or combined ISRE and GAS composite sites in a phosphorylation- and time-dependent manner. Interestingly, composite genes displayed a more heterogeneous expression pattern, as compared to GAS (early) and ISRE genes (late), with the time- and phosphorylation-dependent recruitment of GAF, ISGF3 and IRF1 after IFNα stimulation and GAF and IRF1 after IFNγ. Moreover, functional composite genes shared features of GAS and ISRE genes through transcription factor co-binding to closely located sites, and were able to sustain IFN responsiveness in STAT1-, STAT2-, IRF9-, IRF1- and IRF9/IRF1-mutant Huh7.5 cells compared to Wt cells. Thus, the ISRE + GAS composite site acted as a molecular switch, depending on the timely available components and transcription factor complexes. Consequently, STAT1, STAT2 and IRF9 were identified as functional composite genes that are part of a positive feedback loop controlling long-term IFNα and IFNγ responses. More important, in the absence of any one of the components, the positive feedback regulation of the ISGF3 and GAF components appeared to be preserved. Together, these findings provide further insight in the existence of a novel ISRE + GAS composite-dependent intracellular amplifier circuit prolonging ISG expression and controlling cellular responsiveness to different types of IFNs and subsequent antiviral activity. It also offers an explanation for the existing molecular and functional overlap between IFN-I- and IFN-II-activated ISG expression.
| S-EPMC10287828 | biostudies-literature
Project description:Evolutionary innovation relies partially on changes in gene regulation. While a growing body of evidence demonstrates that such innovation is generated by functional changes or translocation of regulatory elements via mobile genetic elements, the de novo generation of enhancers from non-regulatory/non-mobile sequences has, to our knowledge, not previously been demonstrated. Here we show evidence for the de novo genesis of enhancers in vertebrates. For this, we took advantage of the massive gene loss following the last whole genome duplication in teleosts to systematically identify regions that have lost their coding capacity but retain sequence conservation with mammals. We found that these regions show enhancer activity while the orthologous coding regions have no regulatory activity. These results demonstrate that these enhancers have been de novo generated in fish. By revealing that minor changes in non-regulatory sequences are sufficient to generate new enhancers, our study highlights an important playground for creating new regulatory variability and evolutionary innovation.
| S-EPMC3206014 | biostudies-literature
Project description:The tumor suppressor p53 has critical roles in regulating lipid metabolism, but whether and how p53 regulates cardiolipin (CL) de novo biosynthesis is unknown. Here, we report that p53 physically interacts with histone deacetylase SIRT6 in vitro and in vivo, and this interaction increases following palmitic acid (PA) treatment. In response to PA, p53 and SIRT6 localize to chromatin in a p53-dependent manner. Chromatin p53 and SIRT6 bind the promoters of CDP-diacylglycerol synthase 1 and 2 (CDS1 and CDS2), two enzymes required to catalyze CL de novo biosynthesis. Here, SIRT6 serves as a co-activator of p53 and effectively recruits RNA polymerase II to the CDS1 and CDS2 promoters to enhance CL de novo biosynthesis. Our findings reveal a novel, cooperative model executed by p53 and SIRT6 to maintain lipid homeostasis.
| S-EPMC6148051 | biostudies-literature