Ezh2 is essential for the generation of functional yolk sac derived erythro-myeloid progenitors

Yolk sac (YS) hematopoiesis is critical for the survival of the embryo and a major source of tissue-resident macrophages that persist into adulthood. Yet, the transcriptional and epigenetic regulation of YS hematopoiesis remains poorly characterized. Here we report that the epigenetic regulator Ezh2 is essential for YS hematopoiesis but dispensable for subsequent aorta–gonad–mesonephros (AGM) blood development. Loss of EZH2 activity in hemogenic endothelium (HE) leads to the generation of phenotypically intact but functionally deficient erythro-myeloid progenitors (EMPs), while the generation of primitive erythroid cells is not affected. EZH2 activity is critical for the generation of functional EMPs at the onset of the endothelial-to-hematopoietic transition but subsequently dispensable. We identify a lack of Wnt signaling downregulation as the primary reason for the production of non-functional EMPs. Together, our findings demonstrate a critical and stage-specific role of Ezh2 in modulating Wnt signaling during the generation of EMPs from YS HE.


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Three independent experiments were performed for most experiments unless stated in the figure legend. All experiments consist more than three biological replicates. All attempts at replication were successful.
Samples were allocated in different groups depending on their genotype and embryonic stages.
Blinding was not performed, consistent with widespread practice in the field for studies of this nature.
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Cell lines were not authenticated. However, mESC has the capacity to differentiate into hematopoietic cells with our in house protocol and it has been validated routinely.
Mycoplasma contamination were tested by PCR and found negative in all routine tests.
No commonly misidentified lines were used.
Ezh2fl/fl (59), Tie2-Cre (23), Vav-iCre (22) and Rosa26-LSL-tdTomato (60) reporter mice used in this study have been previously described. All mice were either on C57BL/6 (CD45.2) background or backcrossed to C57BL/6 (>5 generations). All mice were bred and maintained in accordance with UK Home Office project license 30/3103 and 70/8472. Embryonic development was estimated considering the day of vaginal plug formation as 0.5 d post-coitum (dpc) and somite pairs (sp). Both male and female mice were used. Genotyping primers are details in Supplementary Table 1. Mice were housed under specific-pathogen-free conditions with standard food and water ad libitum in a 12h light / 12h dark cycle. Humidity and ambient temperature were maintained between 45-65% and 20-24°C, respectively.
No wild animals were used in the study.
No field collected samples were used in the study.
All experimental procedures and mouse breeding and maintenance were in accordance with United Kingdom Home Office regulations. All experiments were approved by the Oxford University Clinical Medicine Ethical Review Committee and Cancer Research United Kingdom-Manchester Institute Animal Welfare and Ethical Review Body.
Data files have been uploaded to GEO: GSE181873.