Project description:The asymmetric localization of maternal biomolecules is critical for body plan development. One of the most popular model organisms for early embryogenesis studies is Xenopus laevis but there is a lack of information in other animal species. Here, we compare the early development of two amphibian species – the frog X. laevis and the axolotl Ambystoma mexicanum. This study aimed to identify asymmetrically localized RNAs along the animal-vegetal axis during the early development of A. mexicanum. For that purpose, we performed spatial transcriptome-wide analysis, which revealed dynamic changes along the animal-vegetal axis classified into the following categories: relocalization, de novo synthesis and degradation. Surprisingly, our results showed that many of the vegetally localized genes, which are important for germ cell development, are degraded during early development. Furthermore, we assessed the motif presence in UTRs of degraded mRNAs and revealed the enrichment of several motifs in RNAs of germ cell markers. Our results suggest novel reorganization of the transcriptome during embryogenesis of A. mexicanum to converge to the similar developmental pattern as the X. laevis.
Project description:To study the function of zebrafish Ybx1 during early embryogenesis, we generated maternal ybx1 (Mybx1) mutant using CRISPR/Cas9 and report the transcriptome-wide changes in comparison to wild-type (WT) embryos. Our analysis reveals a dramatic loss of maternal mRNA decay and zygotic genome activation in Mybx1 embryos during maternal-to-zygotic transition.
Project description:Humans and other tetrapods are considered to require apical-ectodermal-ridge, AER, cells for limb development, and AER-like cells are suggested to be re-formed to initiate limb regeneration. Paradoxically, the presence of AER in the axolotl, the primary regeneration model organism, remains controversial. Here, by leveraging a single-cell transcriptomics-based multi-species atlas, composed of axolotl, human, mouse, chicken, and frog cells, we first established that axolotls contain cells with AER characteristics. Surprisingly, further analyses and spatial transcriptomics revealed that axolotl limbs do not fully re-form AER cells during regeneration. Moreover, the axolotl mesoderm displays part of the AER machinery, revealing a novel program for limb (re)growth. These results clarify the debate about the axolotl AER and the extent to which the limb developmental program is recapitulated during regeneration.
Project description:To study the function of zebrafish nuclear pores during early embryogenesis, we generated maternal zygotic double mutant of nup85;nup133 (MZnup85;nup133) using CRISPR/Cas9 and report the transcriptome-wide changes in comparison to wild-type (WT) embryos. Our analysis reveals a dramatic delay of maternal mRNA degradation and zygotic genome activation in MZnup85;nup133 embryos during maternal-to-zygotic transition.
Project description:Critical roles for DNA methylation in embryonic development are well established, but less is known about the roles of DNA methylation during trophoblast development, the extraembryonic lineage that gives rise to the placenta. Here we dissected the role of DNA methylation in trophoblast development by performing mRNA and DNA methylation profiling of Dnmt3a/3b-null trophoblast. We find that most gene deregulation is explained by an erasure of maternal methylation in the oocyte, but partially independent of loss of imprinting of the trophoblast-essential Ascl2 gene. Our results reveal that maternal DNA methylation controls multiple differentiation and physiological processes in trophoblast via both imprinting-dependent and -independent mechanisms. mRNA-seq and WGBS-seq of maternal Dnmt3a/3b-null trophoblast; mRNA-seq of maternal Ascl2 KO trophoblast