Project description:A major role of yolk sac endoderm is the uptake of lipids and other constituents from the yolk and transfer of these components into the embryonic circulation. The molecular basis of the initial step of this regionalization has largely remained unclear. Using chick as a model system, we generated high-quality transcriptomic datasets of different stages of the yolksac endoderm and analyzed their molecular heterogeneity. Two independent samples of total RNA were isolated from yolk sac endodermal tissues on embryonic day 1, 2, 3, and 4. 5 M-NM-<g of RNA from each sample (total of 8 samples) were used to screen Affymetrix Chicken Genome Array without an amplification step.
Project description:Post-translational modifications of proteins are crucial to the regulation of their activity and function. As a newly discovered acylation modification, crotonylation of non-histone proteins remains largely unexplored, particularly in human embryonic stem cells (hESCs). Here we report the investigation of induced crotonylation in hESCs, which resulted in hESCs of different pluripotency states differentiating into the endodermal lineage. We showed that increased protein crotonylation in hESCs was accompanied by transcriptomic shifts and decreased glycolysis. Through large-scale profiling of non-histone protein crotonylation, we identified metabolic enzymes as major targets of inducible crotonylation in hESCs. We further discovered GAPDH as a key glycolytic enzyme regulated by crotonylation during endodermal differentiation from hESCs, where crotonylation of GAPDH decreased its enzymatic activity thereby leading to reduced glycolysis. Our study demonstrates that crotonylation of glycolytic enzymes may be crucial to metabolic switching and cell fate determination in hESCs.
Project description:Early development in humans is characterised by low and variable embryonic viability, reflected in low fecundity and high rates of miscarriage, relative to other mammals. Data from assisted reproduction programmes provides additional evidence that this is largely mediated at the level of embryonic competence and is highly heterogeneous among embryos. Understanding the basis of this heterogeneity has important implications in a number of areas including: the regulation of early human development, disorders of pregnancy, assisted reproduction programmes, the long term health of children which may be programmed in early development, and the molecular basis of pluripotency in human stem cell populations. We have therefore investigated global gene expression profiles using polyAPCR amplification and microarray technology applied to individual human oocytes and 4-cell and blastocyst stage embryos. In order to explore the basis of any variability in detail, each developmental stage is replicated in triplicate. Our data show that although transcript profiles are highly stage-specific, within each stage they are relatively variable.
Project description:Metabolism is vital to cellular function and tissue homeostasis during human lung development. In utero, embryonic pluripotent stem cells undergo endodermal differentiation towards a lung progenitor cell fate that can be mimicked in vitro using induced human pluripotent stem cells (hiPSCs) to study genetic mutations. To identify differences between wild type and surfactant protein B (SFTPB)-deficient cell lines during endoderm specification towards lung, we used an untargeted metabolomics approach to evaluate the developmental changes in metabolites. We found that the metabolites most enriched during the differentiation from pluripotent stem cell to lung progenitor cell, regardless of cell line, were sphingomyelins and phosphatidylcholines, two important lipid classes in fetal lung development. The SFTPB mutation had no metabolic impact on early endodermal lung development. The identified metabolite signatures during lung progenitor cell differentiation may be utilized as biomarkers for normal embryonic lung development.
Project description:Because maturing oocytes and early embryos lack transcription, posttranscriptional regulatory processes must control their development. To better understand this control, we profiled translational efficiencies and poly(A)-tail lengths throughout Drosophila oocyte maturation and early embryonic development. The correspondence between translational-efficiency changes and tail-length changes indicated that tail-length changes broadly reshape translational activity until gastrulation, when this coupling disappears. Relative changes were largely retained in the absence of poly(A)-tail lengthening, which indicated that selective poly(A)-tail shortening primarily specifies the changes. Many translational changes depended on PAN GU and Smaug, and both acted primarily through tail-length changes. Our results also revealed tail-lengthâindependent mechanisms of translational control that repressed translation regardless of tail-length changes during oocyte maturation, maintained translation despite tail-length shortening during oocyte maturation, and prevented detectable translation of bicoid and several other mRNAs before egg activation. In addition to these fundamental insights, our results provide valuable resources for future studies. 42 samples analyzed using RNA-seq, ribosome footprint profiling, and PAL-seq.
Project description:Models the production and degradation of cyclin B that drives the early embryonic cell cycle.
Cyclin B is degraded by APC/C. The activity of APC/C is modeled not through biochemical interactions, but through a 'functional response curve'. This can be ultrasensitive (with the parameter alpha=0). in this case the system does not oscillate. Importantly the response can be made bistable and the form of the bistability can be easily prescribed. With a bistable response, the system oscillates.
The uploaded file corresponds to the model used for Figs.3H, I in the publication.
Project description:Unraveling complex signaling programs animating developmental lineage-decisions is pivotal to differentiate human pluripotent stem cells (hPSC) into pure populations of desired lineages for regenerative medicine. Developmental signals are strikingly temporally dynamic: BMP and Wnt initially specify primitive streak (progenitor to endoderm) yet 24 hours later suppress endoderm and induce mesoderm. At lineage bifurcations we show mutually-exclusive embryonic lineages are segregated through cross-repressive signals: TGFM-NM-2 and BMP/MAPK duel to respectively specify pancreas versus liver from endoderm. Unilateral endodermal differentiation requires blockade of alternative fates at every stage, revealing a universal developmental strategy for efficient differentiation and anterior-posterior patterning of diverse hPSC lines into highly-pure endodermal populations. This culminated in hPSC-derived hepatic progenitors that, for the first time, engraft long-term in genetically-unconditioned mouse livers and secrete human albumin. Finally, thirty transcriptional and chromatin state maps capturing endoderm commitment revealed endodermal enhancers reside in an unanticipated diversity of "pre-enhancer" chromatin states before activation. Endoderm RNA-seq and ChIP-seq data sets
Project description:Because maturing oocytes and early embryos lack transcription, posttranscriptional regulatory processes must control their development. To better understand this control, we profiled translational efficiencies and poly(A)-tail lengths throughout Drosophila oocyte maturation and early embryonic development. The correspondence between translational-efficiency changes and tail-length changes indicated that tail-length changes broadly reshape translational activity until gastrulation, when this coupling disappears. Relative changes were largely retained in the absence of poly(A)-tail lengthening, which indicated that selective poly(A)-tail shortening primarily specifies the changes. Many translational changes depended on PAN GU and Smaug, and both acted primarily through tail-length changes. Our results also revealed tail-length–independent mechanisms of translational control that repressed translation regardless of tail-length changes during oocyte maturation, maintained translation despite tail-length shortening during oocyte maturation, and prevented detectable translation of bicoid and several other mRNAs before egg activation. In addition to these fundamental insights, our results provide valuable resources for future studies.
Project description:Post-translational modifications of proteins are crucial to the regulation of their activity and function. As a newly discovered acylation modification, crotonylation of non-histone proteins remains largely unexplored, particularly in human embryonic stem cells (hESCs). Here we report the investigation of induced crotonylation in hESCs, which resulted in hESCs of different pluripotency states differentiating into the endodermal lineage. We showed that increased protein crotonylation in hESCs was accompanied by transcriptomic shifts and decreased glycolysis. Through large-scale profiling of non-histone protein crotonylation, we showed that metabolic enzymes were major targets of inducible crotonylation in hESCs. We further discovered GAPDH as a key glycolytic enzyme regulated by crotonylation during endodermal differentiation from hESCs, where crotonylation of GAPDH decreased its enzymatic activity thereby leading to reduced glycolysis. Our study demonstrates that crotonylation of glycolytic enzymes may be crucial to metabolic switching and cell fate determination in hESCs.