Project description:Genetic control of pluripotent mammalian ES cells is determined by a transcriptional network, with a "central core" of transcription factors, Pou5f1, Sox2 and Nanog. Zebrafish homologues of the "core pluripotency factors" Pou5f1, SoxB1 and Nanog-like are also crucially involved in early development. However, the degree of functional similarity of the network between mammals and non-mammals is a matter of debate. To identify the components of Pou5f1-dependent transcriptional networks, we determined the genomic binding sites for Pou5f1 and Sox2 in late blastula stage zebrafish embryos using ChIP-seq. We found that Sox2 and Pou5f1 are co-binding to the regulatory regions of Sox2, Pou5f1, and Nanog-like, as well as to multiple orthologues of mammalian plutipotency network components. Deep sequencing was performed using the Illumina GAIIx on DNA samples obtained from Sox2 ChIP, Pou5f1-Flag ChIP and Input Control. Pou5f1 was analysed in technical duplicates to obtain higher sequencing depth.
Project description:Genetic control of pluripotent mammalian ES cells is determined by a transcriptional network, with a "central core" of transcription factors, Pou5f1, Sox2 and Nanog. Zebrafish homologues of the "core pluripotency factors" Pou5f1, SoxB1 and Nanog-like are also crucially involved in early development. However, the degree of functional similarity of the network between mammals and non-mammals is a matter of debate. To identify the components of Pou5f1-dependent transcriptional networks, we determined the genomic binding sites for Pou5f1 and Sox2 in late blastula stage zebrafish embryos using ChIP-seq. We found that Sox2 and Pou5f1 are co-binding to the regulatory regions of Sox2, Pou5f1, and Nanog-like, as well as to multiple orthologues of mammalian plutipotency network components.
Project description:Upon fertilization, maternal factors direct development in a transcriptionally silent embryo. At the maternal-to-zygotic transition (MZT), a universal step in animal development, unknown maternal factors trigger zygotic genome activation (ZGA). In zebrafish, ZGA is required for gastrulation and clearance of maternal mRNAs, which is achieved in part by the conserved microRNA miR-430. However, the precise factors that activate the zygotic program remain largely unknown. Here we show that Nanog, Pou5f1 and SoxB1 are required for genome activation in zebrafish. We identified several hundred genes directly activated by maternal factors, thus constituting the first wave of zygotic transcription in zebrafish. Ribosome profiling in the pre-MZT embryo revealed that nanog, sox19b and pou5f1 are the most highly translated transcription factor mRNAs. Combined loss of function for Nanog, SoxB1 and Pou5f1 resulted in developmental arrest prior to gastrulation, and a failure to activate >75% of zygotic genes. Furthermore, we found that Nanog binds the miR-430 locus and together with Pou5f1 and SoxB1 initiate miR-430 expression and activity. Our results demonstrate that maternal Nanog, Pou5f1 and SoxB1 are required to initiate the zygotic developmental program and in turn trigger the clearance of the maternal program by activating miR-430 expression.
Project description:Upon fertilization, maternal factors direct development in a transcriptionally silent embryo. At the maternal-to-zygotic transition (MZT), a universal step in animal development, unknown maternal factors trigger zygotic genome activation (ZGA). In zebrafish, ZGA is required for gastrulation and clearance of maternal mRNAs, which is achieved in part by the conserved microRNA miR-430. However, the precise factors that activate the zygotic program remain largely unknown. Here we show that Nanog, Pou5f1 and SoxB1 are required for genome activation in zebrafish. We identified several hundred genes directly activated by maternal factors, thus constituting the first wave of zygotic transcription in zebrafish. Ribosome profiling in the pre-MZT embryo revealed that nanog, sox19b and pou5f1 are the most highly translated transcription factor mRNAs. Combined loss of function for Nanog, SoxB1 and Pou5f1 resulted in developmental arrest prior to gastrulation, and a failure to activate >75% of zygotic genes. Furthermore, we found that Nanog binds the miR-430 locus and together with Pou5f1 and SoxB1 initiate miR-430 expression and activity. Our results demonstrate that maternal Nanog, Pou5f1 and SoxB1 are required to initiate the zygotic developmental program and in turn trigger the clearance of the maternal program by activating miR-430 expression. Wild type and loss-of-function total mRNA sequencing of embryonic transcriptomes pre- and post-MZT; ribosome profiling pre-MZT
Project description:Pou5f1 and Sox2 overexpression experiments with protein synthesis inhibitor were performed to investigate direct transcriptional targets of Pou5f1 and Sox2
Project description:Pou5f1 and Sox2 overexpression experiments with and without protein synthesis inhibitor were performed to investigate direct transcriptional targets of Pou5f1 and Sox2
Project description:Pou5f1 and Sox2 overexpression experiments with protein synthesis inhibitor were performed to investigate direct transcriptional targets of Pou5f1 and Sox2 Experiments were performed in biological triplicates. Cy3 and Cy5 channels were split and analyzed separately using Genedata Analyst software, quantile normalised and used for independent comparisons.
Project description:In this study, we aimed to identify CRC treatment resistance mechanisms by focusing on POU5F1-positive cells. Despite the small number of POU5F1-positive cells, single POU5F1-expressing cells produced heterogeneous cell populations in vitro and in vivo colorectal cancer organod. This study unveils a mechanism of CRC treatment resistance and highlights the potential of POU5F1-expressing cells as CTCs.