Project description:Maternal-to-zygotic transition (MZT) is a conserved and fundamental process during which the maternal environment of oocyte transits to the zygotic genome driven expression program, and terminally differentiated oocyte and sperm are reprogrammed to totipotency. It is initiated by maternal mRNAs and proteins during the period of zygotic genome quiescence after fertilization, followed by a gradual switch to zygotic genome activation and accompanied by clearance of maternal RNAs and proteins. A key question for embryonic development is how MZT process is regulated. Here we used a low-input proteomic analysis to measure the proteomic dynamics during early development of mouse maternal-to-zygotic transition.
Project description:Maternal-to-zygotic transition (MZT) is a conserved and fundamental process during which the maternal environment of oocyte transits to the zygotic genome driven expression program, and terminally differentiated oocyte and sperm are reprogrammed to totipotency. Metaphase II (MII) oocytes and zygotes (one-cell embryo) serve as the mature oocyte and the initiation of pre-implantation embryo development respectively, and characterizing their molecular landscapes at protein levels plays an important role in uncovering MZT and zygotic genome activation (ZGA )in mammals. Here we used an ultrasensitive proteomic approach to depict an in-depth landscape for the very early stage of mouse MZT.
Project description:We generated maternal and paternal mouse models with Yap1-deletion, and elucidated the function of maternal YAP in zygotic genome activation.
Project description:Zygotic genome activation (ZGA) is essential for early embryonic development. However, the regulation of ZGA remains elusive in mammals. Here we report that a maternal factor TDP-43, a nuclear transactive response DNA-binding protein, regulates ZGA through RNA Pol II and is essential for mouse early embryogenesis. Maternal TDP-43 translocates from the cytoplasm into the nucleus at the early two-cell stage when minor to major ZGA transition occurs. Genetic deletion of maternal TDP-43 results in mouse early embryos arrested at late two-cell stage and female infertile. TDP-43 co-occupies with RNA Pol II as large foci in the nucleus and also at the promoters of ZGA genes at the late two-cell stage. Biochemical evidence indicates that TDP-43 binds Polr2a and Cyclin T1. Depletion of maternal TDP-43 caused the loss of Pol II foci and reduced Pol II binding on chromatin at major ZGA genes, accompanied by defective ZGA. Collectively, our results suggest that maternal TDP-43 is critical for mouse early embryonic development, in part through facilitating the correct RNA Pol II configuration and zygotic genome activation.
Project description:We generated maternal and paternal mouse models with Yap1-deletion, and elucidated the function of maternal YAP in zygotic genome activation. RNA sequencing with 2 WT oocyte samples at GV stage, 2 YAP-/- oocyte samples at GV stage, 1 WT embryo samples at 4cell stage, 1 YAP-/- embryo samples at at 4-cell stage.
Project description:Zygotic gene expression programs control cell differentiation in vertebrate development. In Xenopus, these programs are initiated by local induction of regulatory genes through maternal signaling activities in the wake of zygotic genome activation (ZGA) at the midblastula transition (MBT). These programs lay down the vertebrate body plan through gastrulation and neurulation, and are accompanied by massive changes in chromatin structure, which increasingly constrain cellular plasticity. Here we report on developmental functions for Brahma related gene 1 (BRG1), a key component of embryonic SWI/SNF chromatin remodeling complexes. Carefully controlled, global BRG1 protein depletion in X. tropicalis and X. laevis leads to embryonic lethality from gastrulation on, similar to BRG1-/- mice. Transcriptome analysis at late blastula, before development becomes arrested, indicates predominantly a role for BRG1 in transcriptional activation of a limited set of genes involved in pattern specification processes and nervous system development. Mosaic analysis by targeted microinjection defines BRG1 as an essential amplifier of gene expression in dorsal (BCNE and Nieuwkoop centers) and ventral (BMP/Vent) signaling centers. By tissue transplantation, we define BRG1-dependent activation of chordin (chrd) transcription in the prospective neural plate (BCNE region) as an essential step in head formation. BRG1-sensitive genes are typically characterized by a robust burst of transcription at MBT. These results define a systemic function for BRG1-containing SWI/SNF chromatin remodelers as a transcriptional amplifier of the gene network that initiates embryonic patterning.
Project description:Zygotic gene expression programs control cell differentiation in vertebrate development. In Xenopus, these programs are initiated by local induction of regulatory genes through maternal signaling activities in the wake of zygotic genome activation (ZGA) at the midblastula transition (MBT). These programs lay down the vertebrate body plan through gastrulation and neurulation, and are accompanied by massive changes in chromatin structure, which increasingly constrain cellular plasticity. Here we report on developmental functions for Brahma related gene 1 (BRG1), a key component of embryonic SWI/SNF chromatin remodeling complexes. Carefully controlled, global BRG1 protein depletion in X. tropicalis and X. laevis leads to embryonic lethality from gastrulation on, similar to BRG1-/- mice. Transcriptome analysis at late blastula, before development becomes arrested, indicates predominantly a role for BRG1 in transcriptional activation of a limited set of genes involved in pattern specification processes and nervous system development. Mosaic analysis by targeted microinjection defines BRG1 as an essential amplifier of gene expression in dorsal (BCNE and Nieuwkoop centers) and ventral (BMP/Vent) signaling centers. By tissue transplantation, we define BRG1-dependent activation of chordin (chrd) transcription in the prospective neural plate (BCNE region) as an essential step in head formation. BRG1-sensitive genes are typically characterized by a robust burst of transcription at MBT. These results define a systemic function for BRG1-containing SWI/SNF chromatin remodelers as a transcriptional amplifier of the gene network that initiates embryonic patterning.