Project description:Embryonic blood cell development occurs via well-defined developmental stages which are recapitulated in vitro by differentiation of embryonic stem cells. This process is tightly regulated by the interaction of tissue- specific and ubiquitous transcription factors with the chromatin landscape in response to outside signals. We previously identified binding motifs for the commonly expressed AP-1 transcription factor family in open chromatin regions specific for early stages of blood specification and thus aimed to study the role of AP-1 for hemangioblast differentiation. Here we show that FOS and JUN together bind to and activate a core set of vascular genes in the hemogenic endothelium and that upon global inhibition of AP-1 by expression of a dominant negative FOS peptide the balance between endothelial and hematopoietic fate is shifted towards blood. Moreover, we demonstrate that in the hemogenic endothelium AP-1 is required for de novo binding of TEAD4, a transcription factor connected to Hippo signaling, to vascular genes. Notably, after the endothelial-to-hematopoietic transition TEAD4 binding is no longer persisting. These findings provide novel mechanistic insights into vascular and hematopoietic development.
Project description:Embryonic blood cell development occurs via well-defined developmental stages which are recapitulated in vitro by differentiation of embryonic stem cells. This process is tightly regulated by the interaction of tissue- specific and ubiquitous transcription factors with the chromatin landscape in response to outside signals. We previously identified binding motifs for the commonly expressed AP-1 transcription factor family in open chromatin regions specific for early stages of blood specification and thus aimed to study the role of AP-1 for hemangioblast differentiation. Here we show that FOS and JUN together bind to and activate a core set of vascular genes in the hemogenic endothelium and that upon global inhibition of AP-1 by expression of a dominant negative FOS peptide the balance between endothelial and hematopoietic fate is shifted towards blood. Moreover, we demonstrate that in the hemogenic endothelium AP-1 is required for de novo binding of TEAD4, a transcription factor connected to Hippo signaling, to vascular genes. Notably, after the endothelial-to-hematopoietic transition TEAD4 binding is no longer persisting. These findings provide novel mechanistic insights into vascular and hematopoietic development.
Project description:Embryonic blood cell development occurs via well-defined developmental stages which are recapitulated in vitro by differentiation of embryonic stem cells. This process is tightly regulated by the interaction of tissue- specific and ubiquitous transcription factors with the chromatin landscape in response to outside signals. We previously identified binding motifs for the commonly expressed AP-1 transcription factor family in open chromatin regions specific for early stages of blood specification and thus aimed to study the role of AP-1 for hemangioblast differentiation. Here we show that FOS and JUN together bind to and activate a core set of vascular genes in the hemogenic endothelium and that upon global inhibition of AP-1 by expression of a dominant negative FOS peptide the balance between endothelial and hematopoietic fate is shifted towards blood. Moreover, we demonstrate that in the hemogenic endothelium AP-1 is required for de novo binding of TEAD4, a transcription factor connected to Hippo signaling, to vascular genes. Notably, after the endothelial-to-hematopoietic transition TEAD4 binding is no longer persisting. These findings provide novel mechanistic insights into vascular and hematopoietic development.
Project description:In the preimplantation mouse embryo TEAD4 is critical to establishing the trophectoderm (TE)-specific transcriptional program and segregating TE from the inner cell mass (ICM). However, TEAD4 is expressed both in the TE and the ICM. Thus, differential function of TEAD4 rather than expression itself regulates specification of the first two cell lineages. We used ChIP-seq to define genome-wide TEAD4 target genes and asked how transcription of TEAD4 target genes is specifically maintained in the TE. Our analyses revealed an evolutionarily conserved mechanism, in which lack of nuclear localization of TEAD4 impairs the TE-specific transcriptional program in inner blastomeres, thereby allowing their maturation towards the ICM lineage. Restoration of TEAD4 nuclear localization maintains the TE-specific transcriptional program in the inner blastomeres and prevents segregation of the TE and ICM lineages and blastocyst formation. We propose that altered subcellular localization of TEAD4 in blastomeres dictates first mammalian cell fate specification. ChIPseq profiles of TEAD4, IgG, Input in Mouse trophoblast stem cells using Illumina HiSeq 2000 and Illumina Genome Analyzer IIx
Project description:In the preimplantation mouse embryo TEAD4 is critical to establishing the trophectoderm (TE)-specific transcriptional program and segregating TE from the inner cell mass (ICM). However, TEAD4 is expressed both in the TE and the ICM. Thus, differential function of TEAD4 rather than expression itself regulates specification of the first two cell lineages. We used ChIP-seq to define genome-wide TEAD4 target genes and asked how transcription of TEAD4 target genes is specifically maintained in the TE. Our analyses revealed an evolutionarily conserved mechanism, in which lack of nuclear localization of TEAD4 impairs the TE-specific transcriptional program in inner blastomeres, thereby allowing their maturation towards the ICM lineage. Restoration of TEAD4 nuclear localization maintains the TE-specific transcriptional program in the inner blastomeres and prevents segregation of the TE and ICM lineages and blastocyst formation. We propose that altered subcellular localization of TEAD4 in blastomeres dictates first mammalian cell fate specification.
Project description:A comprehensive analysis of Sox9 binding profiles in developing chondrocytes identified marked enrichment of an AP-1-like motif (Ohba et al. 2015). Here, we have explored the functional interplay between Sox9 and AP-1 in mammalian chondrocyte development. Among AP-1 family members, Jun and Fosl2 were highly expressed within prehypertrophic and early hypertrophic chondrocytes. Chromatin immunoprecipitation followed by DNA sequencing (ChIP-seq) showed a striking overlap in Jun- and Sox9-bound regions throughout the chondrocyte genome, a reflection of direct binding of each factor to target motifs in shared enhancers, and physical interactions of AP-1 with Sox9. In vitro expression analysis indicates that direct co-binding of Sox9 and AP-1 at target motifs enhanced target gene expression, while protein-protein interactions suppressed AP-1- and Sox9-driven transcription. Analysis of prehypertrophic chondrocyte removal of Sox9 demonstrated Sox9 was essential for hypertrophic chondrocyte development, while in vitro and ex vivo analyses showed AP-1 promotes chondrocyte hypertrophy. Sox9 and Jun co-bound and co-activated a Col10a1 enhancer in Sox9 and AP-1 motif-dependent manners consistent with their combined action promoting hypertrophic gene expression. Together, the data support a model where AP-1-family members promote Sox9-action in the transition of chondrocytes to a terminal hypertrophic program. Intersection of ChIP-seq data from Sox9 and AP-1 factor Jun, RNA-seq data from developing rib chondrocytes and Col10a1mCherry positive hypertrophic chondrocytes in neonatal mice to uncover regulation of Sox9 by AP-1 factors during chondrocyte hypertrophy.
Project description:We sequenced mRNA from zebrafish wild-type embryos, gata5 morphants, gata6 morphants, and gata5/6 morphants at bud and 6-somite developmental stages to identify genes co-operatively regulated by gata5 and gata6 during cardiomyocyte progenitor specification.