blastomeres

Human embryo at day four | Image Editor


Scanning electron micrograph of a human embryo at day 4. The protein coat surrounding the egg (zona pellucida, gold) has been slit to expose the embryonic cells inside (red). These cells go on to form the embryo and can be harvested and cultured to give rise to embryonic stem (ES) cells. Microvilli are visible on the surface of the embryonic cells (blastomeres) and numerous sperm (blue) are still visible on the outside of the zona pellucida.

vimeo

Splitting Heirs

Each of these boxes holds the early signs of new human life. The video shows blastomeres – the cells formed from a fertilized egg – dividing at first into two cells, then two into four. Cell division at this delicate stage must be precise: the DNA received just hours ago from mother and father must be split equally between dividing cells. Unequal division, known as aneuploidy, can lead to birth defects or diseases in later life. DNA inside some of these blastomeres is breaking off into unequal fragments (see the troubled blastomere in the centre of the bottom row). The overlaid coloured spots show a computer program scanning the blastomeres for such fragments – effectively screening for ‘faulty’ embryos. Knowing which embryos are likely to develop healthily prior to injection into the uterus could increase the success of future IVF treatments and decrease the risk of miscarriage during pregnancy.

Written by John Ankers

Dynamic expression of chromatin modifiers during developmental transitions in mouse preimplantation embryos

During mouse preimplantation development, major changes in cell fate are accompanied by extensive alterations of gene expression programs. Embryos first transition from a maternal to zygotic program and subsequently specify the pluripotent and the trophectodermal cell lineages. These processes are regulated by key transcription factors, likely in cooperation with chromatin modifiers that control histone and DNA methylation. To characterize the spatiotemporal expression of chromatin modifiers in relation to developmental transitions, we performed gene expression profiling of 156 genes in individual oocytes and single blastomeres of developing mouse embryos until the blastocyst stage. More than half of the chromatin modifiers displayed either maternal or zygotic expression. We also detected lineage-specific expression of several modifiers, including Ezh1, Prdm14, Scmh1 and Tet1 underscoring possible roles in cell fate decisions. Members of the SET-domain containing SMYD family showed differential gene expression during preimplantation development. We further observed co-expression of genes with opposing biochemical activities, such as histone methyltransferases and demethylases, suggesting the existence of a dynamic chromatin steady-state during preimplantation development.

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fromnakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/1PEodlQ
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Dynamic expression of chromatin modifiers during developmental transitions in mouse preimplantation embryos

During mouse preimplantation development, major changes in cell fate are accompanied by extensive alterations of gene expression programs. Embryos first transition from a maternal to zygotic program and subsequently specify the pluripotent and the trophectodermal cell lineages. These processes are regulated by key transcription factors, likely in cooperation with chromatin modifiers that control histone and DNA methylation. To characterize the spatiotemporal expression of chromatin modifiers in relation to developmental transitions, we performed gene expression profiling of 156 genes in individual oocytes and single blastomeres of developing mouse embryos until the blastocyst stage. More than half of the chromatin modifiers displayed either maternal or zygotic expression. We also detected lineage-specific expression of several modifiers, including Ezh1, Prdm14, Scmh1 and Tet1 underscoring possible roles in cell fate decisions. Members of the SET-domain containing SMYD family showed differential gene expression during preimplantation development. We further observed co-expression of genes with opposing biochemical activities, such as histone methyltransferases and demethylases, suggesting the existence of a dynamic chromatin steady-state during preimplantation development.

frommeraentaxei on Inoreader http://ift.tt/1nrYc2z
via IFTTT

fromnakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/1nCqIiw
via IFTTT

from on Inoreader http://ift.tt/20x2OTH
via IFTTT

Dynamic expression of chromatin modifiers during developmental transitions in mouse preimplantation embryos

During mouse preimplantation development, major changes in cell fate are accompanied by extensive alterations of gene expression programs. Embryos first transition from a maternal to zygotic program and subsequently specify the pluripotent and the trophectodermal cell lineages. These processes are regulated by key transcription factors, likely in cooperation with chromatin modifiers that control histone and DNA methylation. To characterize the spatiotemporal expression of chromatin modifiers in relation to developmental transitions, we performed gene expression profiling of 156 genes in individual oocytes and single blastomeres of developing mouse embryos until the blastocyst stage. More than half of the chromatin modifiers displayed either maternal or zygotic expression. We also detected lineage-specific expression of several modifiers, including Ezh1, Prdm14, Scmh1 and Tet1 underscoring possible roles in cell fate decisions. Members of the SET-domain containing SMYD family showed differential gene expression during preimplantation development. We further observed co-expression of genes with opposing biochemical activities, such as histone methyltransferases and demethylases, suggesting the existence of a dynamic chromatin steady-state during preimplantation development.

fromia o.lakala70 on Inoreader http://ift.tt/1nrYc2z
via IFTTT

from on Inoreader http://ift.tt/1PEodlQ
via IFTTT

Dynamic expression of chromatin modifiers during developmental transitions in mouse preimplantation embryos

During mouse preimplantation development, major changes in cell fate are accompanied by extensive alterations of gene expression programs. Embryos first transition from a maternal to zygotic program and subsequently specify the pluripotent and the trophectodermal cell lineages. These processes are regulated by key transcription factors, likely in cooperation with chromatin modifiers that control histone and DNA methylation. To characterize the spatiotemporal expression of chromatin modifiers in relation to developmental transitions, we performed gene expression profiling of 156 genes in individual oocytes and single blastomeres of developing mouse embryos until the blastocyst stage. More than half of the chromatin modifiers displayed either maternal or zygotic expression. We also detected lineage-specific expression of several modifiers, including Ezh1, Prdm14, Scmh1 and Tet1 underscoring possible roles in cell fate decisions. Members of the SET-domain containing SMYD family showed differential gene expression during preimplantation development. We further observed co-expression of genes with opposing biochemical activities, such as histone methyltransferases and demethylases, suggesting the existence of a dynamic chromatin steady-state during preimplantation development.

frommeraentaxei on Inoreader http://ift.tt/1nrYc2z
via IFTTT

from on Inoreader http://ift.tt/1nCqIiw
via IFTTT