Analysis Tools
cellular
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• at E6.5, nuclear areas are significantly larger throughout the embryo
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• at E6.5, embryos accumulate Rab7positive late endosomes and fail to disperse lysosomes; lysosomal clustering is observed, indicating defects in lysosomal positioning
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• at E6.5, embryos show a vastly decreased total number of cells, with a significant increase in the percent of apoptotic TUNEL+ cells
• apoptotic cells are distributed throughout embryos, with no increased presence in any particular lineage
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• E6.5 embryos have significantly fewer epiblast cells than both E6.5 and E5.5 wild-type embryos, suggesting that while the extraembryonic lineages continue to proliferate, the epiblast does not
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• at E6.5, embryos show clustering of lysosomes and improper degradation of late endosomes through fusion with lysosomes
• large discrete patches of Rab7 (a marker for late endosomes) and Lamp1 (a lysosome marker) are observed, suggesting a failure of lysosomes to be transported to endosomes for endosomal degradation
• moreover, the vesicles encapsulated by these membrane markers are much larger and more densely packed, suggesting that breakdown of vesicle contents is defective
• analysis of fluorescent dextran uptake shows that endocytosed dextran647 remains in the visceral endoderm sequestered in small, concentrated vesicles, suggesting that endosomes are not properly degraded; no dextran647 is noted in the epiblast, indicating defects in transport between the visceral endoderm and epiblast
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embryo
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• at E6.5, embryos show a vastly decreased total number of cells, with a significant increase in the percent of apoptotic TUNEL+ cells
• apoptotic cells are distributed throughout embryos, with no increased presence in any particular lineage
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• at E6.5, the ratio of epiblast to extraembryonic ectoderm is significantly smaller than in wild-type embryos
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• no features typical of gastrulating embryos are observed at E7.5
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• embryos arrest prior to gastrulation
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• at E7.5, a large cavity is observed between the Reichert's membrane (RM) and the embryo; however, the RM shows normal size and expansion
• at E6.5, embryos lack epithelial organization and exhibit fewer and larger cells characterized by large nuclei
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• embryos are much smaller than controls at E7.5
(J:279207)
• embryos are of normal overall size at E6.5 but severely reduced in size at E7.5
(J:329966)
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• epiblast appears to have died at E7.5
• at E6.5, cell area is significantly increased in the epiblast
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• E6.5 embryos have significantly fewer epiblast cells than both E6.5 and E5.5 wild-type embryos, suggesting that while the extraembryonic lineages continue to proliferate, the epiblast does not
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• at E6.5, the epiblast is much smaller with significantly fewer Pou5f1/Oct4+ cells; the epiblast is only half of the height of the extraembryonic ectoderm
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• a rudimentary egg cylinder has formed at E6.5 but degenerates by E7.5
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• no head folds are present at E7.5
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• no embryonic node is present at E7.5
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• ISH shows variable expression of Brachyury (a marker of the nascent primitive streak) at E6.5
• none of the embryos show robust Brachyury expression localized to the presumptive posterior of the embryo, indicating that the primitive streak is not properly organized at E6.5
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• no morphological evidence of primitive streak formation is observed at E7.5
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• extraembryonic ectoderm appears to have died at E7.5
• at E6.5, cell area is significantly increased in the extraembryonic ectoderm
• E6.5 embryos have significantly fewer extraembryonic ectoderm cells than E6.5 wild-type embryos but show no significant change relative to E5.5 wild-type embryos
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• abnormally large visceral endoderm cells are detected at E7.5
• at E6.5, embryos exhibit large, discrete Rab7+ vesicles primarily in the visceral endoderm, indicating accumulation of late endosomes
• at E6.5, late endosomes and lysosomes are dispersed evenly throughout the visceral endoderm, with no apparent difference in the proximal vs distal parts, unlike in wild-type embryos where more late endosomes and lysosomes are seen in the proximal than in the distal half
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• at E6.5, very large cells are noted in the distal half of the visceral endoderm; the visceral endoderm surrounding the epiblast (distal half) is significantly thicker than in wild-type controls
• however, the thickness of the visceral endoderm surrounding the extraembryonic ectoderm (proximal half) is not significantly altered
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growth/size/body
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• embryos are much smaller than controls at E7.5
(J:279207)
• embryos are of normal overall size at E6.5 but severely reduced in size at E7.5
(J:329966)
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mortality/aging
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IMPC - JAX
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IMPC - JAX
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• homozygous embryos are found in normal Mendelian ratios at E6.5 and E7.5 but not recovered at E9.5 or at birth
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• homozygous embryos are recovered in expected ratios at E7.5 but arrest prior to gastrulation
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