Cell and tissue requirements for the gene eed during mouse gastrulation and organogenesis

Abstract

Mouse embryos homozygous for the allele eed(l7Rn5-3354SB) of the Polycomb Group gene embryonic ectoderm development (eed) display a gastrulation defect in which epiblast cells move through the streak and form extraembryonic mesoderm derivatives at the expense of development of the embryo proper. Here we demonstrate that homozygous mutant ES cells have the capacity to differentiate embryonic cell types both in vitro as embryoid bodies and in vivo as chimeric embryos. In chimeric embryos, eed mutant cells can respond to wild-type signals and participate in normal gastrulation movements. These results indicate a non-cell-autonomous function for eed. Evidence of mutant cell exclusion from the forebrain and segregation within somites, however, suggests that eed has cell-autonomous roles in aspects of organogenesis. A requirement for eed in the epiblast during embryonic development is supported by the fact that high-contribution chimeras could not be rescued by a wild-type extraembryonic environment.

The Polycomb Group Protein Suz12 Is Required for Embryonic Stem Cell Differentiation

“…Histone modifying enzymes, like the PRCs, are believed to play a critical role in this pro- VOL. 27,2007 Suz12 IS REQUIRED FOR ES CELL DIFFERENTIATION 3777 cess. PRC2 is required for correct expression of the HOX genes in later development (1,20,34), but defects in embryos lacking functional PRC2 arise earlier than HOX expression, suggesting additional functions of the complex (16,30,32).…”

Consequences of the depletion of zygotic and embryonic enhancer of zeste 2 during preimplantation mouse development

“…The Ezh2 may therefore be crucial for the propagation of the pluripotent state and during the early stages of cell fate determination, which is consistent with the early embryonic lethality of Ezh2 -/-embryos. By contrast, Eed mutant blastocysts give rise to ES cells and these mutant ES cells contribute to chimeric mice, indicating a fundamental difference in the importance of these proteins for pluripotent cells (Morin-Kensicki et al, 2001). …”

HEB associates with PRC2 and SMAD2/3 to regulate developmental fates

“…Three biological replicates from shControl or shHEB-targeted cells were prepared for each cell type: ESC and differentiated EB in the serum-free defined culture system, with or without Activin treatment. Total RNA was isolated using the RNeasy Plus Mini Kit (Qiagen) and then mRNA was purified using Dynabeads Oligo(dT) 25 (Invitrogen). The mRNA (400 ng) was heat sheared and reverse transcribed with a custom P7 oligo(dT)_Index primer containing Illumina-compatible adaptor sequence.…”

“…We next tested whether PRC2 is required for HEB binding at developmental promoters. To this end, we examined HEB occupancy in Eed homozygous mutant (Eed-/-) ESCs, which have disruption of PRC2-mediated H3K27 methylation, but can maintain ESC pluripotency on mouse embryonic fibroblasts (MEFs) 7,25,26,35,44 ( Supplementary Fig. 8a,b).…”

“…In the mouse embryo, each PRC2 component is necessary for gastrulation, demonstrating an important in vivo role for PRC2 in lineage determination 7,[23][24][25][26] . Likewise, in mouse ESCs, while these proteins are not essential for pluripotency, EED, SUZ12 and EZH2 are necessary for appropriate lineage specification, strongly suggesting that PRC2 is a general regulator of the transition from pluripotency toward more specific cellular fates 7,23,24 .…”