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Resolving early mesoderm diversification through single-cell expression profiling.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Scialdone, Antonio 
Tanaka, Yosuke 
Wilson, Nicola K 

Abstract

In mammals, specification of the three major germ layers occurs during gastrulation, when cells ingressing through the primitive streak differentiate into the precursor cells of major organ systems. However, the molecular mechanisms underlying this process remain unclear, as numbers of gastrulating cells are very limited. In the mouse embryo at embryonic day 6.5, cells located at the junction between the extra-embryonic region and the epiblast on the posterior side of the embryo undergo an epithelial-to-mesenchymal transition and ingress through the primitive streak. Subsequently, cells migrate, either surrounding the prospective ectoderm contributing to the embryo proper, or into the extra-embryonic region to form the yolk sac, umbilical cord and placenta. Fate mapping has shown that mature tissues such as blood and heart originate from specific regions of the pre-gastrula epiblast, but the plasticity of cells within the embryo and the function of key cell-type-specific transcription factors remain unclear. Here we analyse 1,205 cells from the epiblast and nascent Flk1(+) mesoderm of gastrulating mouse embryos using single-cell RNA sequencing, representing the first transcriptome-wide in vivo view of early mesoderm formation during mammalian gastrulation. Additionally, using knockout mice, we study the function of Tal1, a key haematopoietic transcription factor, and demonstrate, contrary to previous studies performed using retrospective assays, that Tal1 knockout does not immediately bias precursor cells towards a cardiac fate.

Description

Keywords

Animals, Basic Helix-Loop-Helix Transcription Factors, Cell Lineage, Embryo, Mammalian, Erythropoiesis, Gastrula, Gastrulation, Gene Expression Profiling, Mesoderm, Mice, Proto-Oncogene Proteins, Sequence Analysis, DNA, Single-Cell Analysis, T-Cell Acute Lymphocytic Leukemia Protein 1, Transcriptome

Journal Title

Nature

Conference Name

Journal ISSN

0028-0836
1476-4687

Volume Title

Publisher

Springer Science and Business Media LLC
Sponsorship
Wellcome Trust (105031/D/14/Z)
Leukaemia & Lymphoma Research (12029)
Cancer Research Uk (None)
Biotechnology and Biological Sciences Research Council (BB/I00050X/1)
Wellcome Trust (097922/Z/11/Z)
Medical Research Council (MC_PC_12009)
Leukemia & Lymphoma Society (7001-12)
Medical Research Council (MR/M008975/1)
Wellcome Trust (100140/Z/12/Z)
Cancer Research UK (22231)
We thank M. de Bruijn, A. Martinez-Arias, J. Nichols and C. Mulas for discussion, the Cambridge Institute for Medical Research Flow Cytometry facility for their expertise in single-cell index sorting, and S. Lorenz from the Sanger Single Cell Genomics Core for supervising purification of Tal1−/− sequencing libraries. ChIP-seq reads were processed by R. Hannah. Research in the authors’ laboratories is supported by the Medical Research Council, Cancer Research UK, the Biotechnology and Biological Sciences Research Council, Bloodwise, the Leukemia and Lymphoma Society, and the Sanger-EBI Single Cell Centre, and by core support grants from the Wellcome Trust to the Cambridge Institute for Medical Research and Wellcome Trust - MRC Cambridge Stem Cell Institute and by core funding from Cancer Research UK and the European Molecular Biology Laboratory. Y.T. was supported by a fellowship from the Japan Society for the Promotion of Science. W.J. is a Wellcome Trust Clinical Research Fellow. A.S. is supported by the Sanger-EBI Single Cell Centre. This work was funded as part of Wellcome Trust Strategic Award 105031/D/14/Z ‘Tracing early mammalian lineage decisions by single-cell genomics’ awarded to W. Reik, S. Teichmann, J. Nichols, B. Simons, T. Voet, S. Srinivas, L. Vallier, B. Göttgens and J. Marioni.