Project description:We report the high-throughput profiling of ISL1-binding sites in mammalian cells. By obtaining over four billion bases of sequence from chromatin immunoprecipitated DNA, we generated genome-wide ISL1-binding maps of SGC7901 cells. This study provides a prediction of regulated genes by the ISL1.
Project description:We report the high-throughput profiling of ISL1-binding sites in mammalian cells. By obtaining over four billion bases of sequence from chromatin immunoprecipitated DNA, we generated genome-wide ISL1-binding maps of Huh7 cells. This study provides a prediction of regulated genes by the ISL1.
Project description:To identify regulatory targets of the transcription factor Isl1 in the developing mouse genitalia, we performed ChIP-Seq using an anti-ISL1 rabbit monoclonal antibody on pooled chromatin isolated from multiple E14.5 mouse embryonic genital tubercles (GT). Our analysis identified more than 7,054 genomic regions enriched in both of two replicates. The majority of these binding sites are located more than 5 kb from the closest annotated transcriptional start site (TSS), with nearly one third of the binding sites more than 50kb away from the nearest TSS. A de novo motif search using HOMER demonstrated that GT Isl1 ChIP-seq peaks are enriched for a motif that matches the consensus sequence bound by Isl1 in other tissues. When compared to active enhancers in the GT identified using H3K27ac ChIP-Seq, we found that Isl1 binding sites are strongly enriched in the GT compared to other embryonic tissues. Further analysis of the location of Isl1 peaks revealed a strong association with genes implicated in limb and urogenital development. We conclude that there is a strong association between Isl1 regulatory activity and genes involved in genital development.
Project description:Understanding factors that drive development and function of the sinoatrial node (SAN) is crucial to development of potential therapies for sinus arrhythmias, including potential generation of biological pacemakers. Here, we identify a key cell autonomous role for the LIM homeodomain transcription factor ISL1 for survival, proliferation and function of pacemaker cells throughout development. Chromatin immunoprecipitation assays performed utilizing antibody to ISL1 in chromatin extracts from FACS purified SAN cells demonstrated that ISL1 directly binds genomic regions within several genes critical for normal pacemaker function, including subunits of the L-type calcium channel, Ank2, and Tbx3. Other genes implicated in abnormal heart rhythm in humans were also direct downstream targets of ISL1 in SAN cells. Our studies represent the first in vivo ChIP-seq studies for SAN cells which provide a basis for further exploration of factors critical to SAN formation and function and highlight the potential for utilization of ISL1 in combination with other SAN transcription factors for generating pacemaker cells for therapy or drug screening purposes. ISL1 ChIP-seq profiling was performed in Hcn4-H2BGFP SAN cells purified from neonatal hearts.
Project description:Generation of widely differing and specialized cell types from a single totipotent zygote involves large-scale transcriptional changes and chromatin reorganization. Pioneer transcription factors play key roles in programming the epigenome and facilitating recruitment of additional regulatory factors during successive cell lineage specification and differentiation steps. Here we show that Isl1 acts as a pioneer factor driving cardiomyocyte lineage commitment by shaping the chromatin landscape of cardiac progenitor cells. Using an Isl1 hypomorphic mouse line which shows congenital heart defects, genome-wide profiling of Isl1 binding together with RNA- and ATAC-sequencing of cardiac progenitor cells and their derivatives, we uncover a regulatory network downstream of Isl1 that orchestrates cardiogenesis. Mechanistically, we show that Isl1 binds to compacted chromatin and woks in concert with the Brg1-Baf60c-based SWI/SNF complex to promote permissive cardiac lineage-specific alterations in the chromatin landscape not only of genes with critical functions in cardiac progenitor cells, but also of cardiomyocyte structural genes that are highly expressed when Isl1 itself is no longer present. Thus, the Isl1/Brg1-Baf60c complex plays a crucial role in orchestrating proper cardiogenesis and in establishing epigenetic memory of cardiomyocyte fate commitment.
Project description:Generation of widely differing and specialized cell types from a single totipotent zygote involves large-scale transcriptional changes and chromatin reorganization. Pioneer transcription factors play key roles in programming the epigenome and facilitating recruitment of additional regulatory factors during successive cell lineage specification and differentiation steps. Here we show that Isl1 acts as a pioneer factor driving cardiomyocyte lineage commitment by shaping the chromatin landscape of cardiac progenitor cells. Using an Isl1 hypomorphic mouse line which shows congenital heart defects, genome-wide profiling of Isl1 binding together with RNA- and ATAC-sequencing of cardiac progenitor cells and their derivatives, we uncover a regulatory network downstream of Isl1 that orchestrates cardiogenesis. Mechanistically, we show that Isl1 binds to compacted chromatin and woks in concert with the Brg1-Baf60c-based SWI/SNF complex to promote permissive cardiac lineage-specific alterations in the chromatin landscape not only of genes with critical functions in cardiac progenitor cells, but also of cardiomyocyte structural genes that are highly expressed when Isl1 itself is no longer present. Thus, the Isl1/Brg1-Baf60c complex plays a crucial role in orchestrating proper cardiogenesis and in establishing epigenetic memory of cardiomyocyte fate commitment.