Multiscale analysis of single and double maternal-zygotic Myh9 and Myh10 mutants during mouse preimplantation development
- Institut Curie, France
Abstract
During the first days of mammalian development, the embryo forms the blastocyst, the structure responsible for implanting the mammalian embryo. Consisting of an epithelium enveloping the pluripotent inner cell mass and a fluid-filled lumen, the blastocyst results from a series of cleavages divisions, morphogenetic movements and lineage specification. Recent studies identified the essential role of actomyosin contractility in driving the cytokinesis, morphogenesis and fate specification leading to the formation of the blastocyst. However, the preimplantation development of contractility mutants has not been characterized. Here, we generated single and double maternal-zygotic mutants of non-muscle myosin II heavy chains (NMHC) to characterize them with multiscale imaging. We find that Myh9 (NMHC II-A) is the major NMHC during preimplantation development as its maternal-zygotic loss causes failed cytokinesis, increased duration of the cell cycle, weaker embryo compaction and reduced differentiation, whereas Myh10 (NMHC II-B) maternal-zygotic loss is much less severe. Double maternal-zygotic mutants for Myh9 and Myh10 show a much stronger phenotype, failing most attempts of cytokinesis. We find that morphogenesis and fate specification are affected but nevertheless carry on in a timely fashion, regardless of the impact of the mutations on cell number. Strikingly, even when all cell divisions fail, the resulting single-celled embryo can initiate trophectoderm differentiation and lumen formation by accumulating fluid in increasingly large vacuoles. Therefore, contractility mutants reveal that fluid accumulation is a cell-autonomous process and that the preimplantation program carries on independently of successful cell division.
Data availability
The microscopy data, ROI and analyses are available on the following repository under a CC BY- NC-SA license: https://ressources.curie.fr/mzmyh/
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Single-cell RNA-Seq reveals dynamic, random monoallelic gene expression in mammalian cellsNCBI Gene Expression Omnibus, GSE45719.
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Tracing pluripotency of human early embryos and embryonic stem cells by single cell RNA-seqNCBI Gene Expression Omnibus, GSE36552.
Article and author information
Author details
Markus Frederik Schliffka
Anna-Francesca Tortorelli
Ludmilla de Plater
Funding
Institut des sciences biologiques
- Diane Pelzer
Agence Nationale de la Recherche (ANR-11-LABX-0044)
- Jean-Léon Maître
Agence Nationale de la Recherche (ANR-10-IDEX-0001-02)
- Jean-Léon Maître
Association Nationale de la Recherche et de la Technologie (2019/0253)
- Markus Frederik Schliffka
H2020 Marie Skłodowska-Curie Actions (666003)
- Özge Özgüç
Institut National de la Santé et de la Recherche Médicale
- Jean-Léon Maître
Fondation pour la Recherche Médicale
- Özge Özgüç
Fondation Schlumberger pour l'Education et la Recherche
- Jean-Léon Maître
H2020 European Research Council (ERC-2017-StG 757557)
- Jean-Léon Maître
European Molecular Biology Organisation
- Jean-Léon Maître
Université de Recherche Paris Sciences et Lettres (17-CONV-0005)
- Jean-Léon Maître
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal work is performed in the animal facility at the Institut Curie, with permission by the institutional veterinarian overseeing the operation (APAFIS #11054- 2017082914226001). The animal facilities are operated according to international animal welfare rules.
Copyright
© 2021, Schliffka et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Further reading
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- Developmental Biology
Wing dimorphism is a common phenomenon that plays key roles in the environmental adaptation of aphid; however, the signal transduction in response to environmental cues and the regulation mechanism related to this event remain unknown. Adenosine (A) to inosine (I) RNA editing is a post-transcriptional modification that extends transcriptome variety without altering the genome, playing essential roles in numerous biological and physiological processes. Here, we present a chromosome-level genome assembly of the rose-grain aphid Metopolophium dirhodum by using PacBio long HiFi reads and Hi-C technology. The final genome assembly for M. dirhodum is 447.8 Mb, with 98.50% of the assembled sequences anchored to nine chromosomes. The contig and scaffold N50 values are 7.82 and 37.54 Mb, respectively. A total of 18,003 protein-coding genes were predicted, of which 92.05% were functionally annotated. In addition, 11,678 A-to-I RNA-editing sites were systematically identified based on this assembled M. dirhodum genome, and two synonymous A-to-I RNA-editing sites on CYP18A1 were closely associated with transgenerational wing dimorphism induced by crowding. One of these A-to-I RNA-editing sites may prevent the binding of miR-3036-5p to CYP18A1, thus elevating CYP18A1 expression, decreasing 20E titer, and finally regulating the wing dimorphism of offspring. Meanwhile, crowding can also inhibit miR-3036-5p expression and further increase CYP18A1 abundance, resulting in winged offspring. These findings support that A-to-I RNA editing is a dynamic mechanism in the regulation of transgenerational wing dimorphism in aphids and would advance our understanding of the roles of RNA editing in environmental adaptability and phenotypic plasticity.
