Mouse developmental genetics

Our main interest is to understand the underlying genetic basis of early cell fate decisions in the mammalian embryo. Using a combination of in vitro screens in mouse embryonic stem cells and mutational analyses in mice, we seek to identify genes that are required for the formation of early cell lineages of the mouse embryo.

Mutations in genes that perturb normal cellular differentiation form the basis of detailed genetic and proteomic studies to elucidate the signalling pathways and regulatory networks that delineate specific developmental programs.

[Professor Alan Boyde, Wellcome Images]

Background

The use of mouse embryonic stem (ES) cells to elucidate diverse areas in biology has great potential and is currently under-utilised. ES cells represent a genetically tractable model system to study basic cell biological and developmental processes on a genome-wide scale. Our work is aimed at establishing gene-based phenotype driven screens in mouse ES cells that will add an important new dimension to the functional annotation of mammalian genes.

Research

Examples of ongoing projects in the Skarnes laboratory

Formation of mesoderm in a gastrulating mouse embryo.

Formation of mesoderm in a gastrulating mouse embryo.

The current focus of our work is to study global changes in gene expression, protein-protein and protein-DNA interactions that accompany ES cell differentiation along specific cell lineages and to perturb the developmental potential of ES cells by genetic mutation. These studies should identify individual genes and genetic pathways that are required for cell fate decisions in the early embryo. A more complete understanding of the program of events associated with ES cell differentiation will suggest ways to drive mouse ES cells along specific cell lineages. Ultimately, it may be possible to engineer and reprogram human stem cells to provide appropriate cell types for somatic cell replacement therapies for the treatment of human disease.

Conditional ablation of gene function in ES cells

Large-scale genetic screens in ES cells is hampered by the difficulty in generating homozygous mutant cells. Moreover, genes essential for the growth of stem cells require conditional strategies to recover and study loss-of-function mutations. Taking advantage of modular targeting vectors and conditional targeted ES cells generated by the ES Cell Mutagenesis team, we are developing high-efficiency strategies for the generation of conditional homozygous mutant ES cells by serial targeting and the use of ligand-inducible Cre recombinase. This approach permits the study of genes required for stem cell pluripotency and self-renewal.

Astrocytes derived from mouse ES cells.

Astrocytes derived from mouse ES cells.

Functional analysis chromatin proteins in early mouse development

It is abundantly clear that packaging of genomic DNA is not equivalent in all cell types and various epigenetic modifications profoundly influence the transcriptional competence of genes and developmental potential of cells.

We are examining the function of chromatin-associated proteins in undifferentiated and differentiated ES cell cultures.

These include components of the SWI/SNF chromatin-remodeling complexes, Polycomb group protein complexes and the nucleosome remodelling and deactylation (NuRD) complexes.

Homozygous mutant embryo (right) fails to develop normally at the gastrulation stage.

Homozygous mutant embryo (right) fails to develop normally at the gastrulation stage.

Proteomic analysis of chromatin proteins in ES cells

As part of the EUTRACC consortium, we have developed and validated a novel strategy for tagging of genes in ES cells for tandem-affinity purification-mass spectrometry (TAP-MS) analysis. This strategy ensures the expression of tagged proteins at endogenous levels and the generation of mice from tagged ES cells can be used to confirm the normal activity of the tagged protein. The analysis of protein-protein and protein-DNA interactions of selected chromatin proteins is currently underway.

  • ES cell pluripotency and germ-layer formation require the SWI/SNF chromatin remodeling component BAF250a.

    Gao X, Tate P, Hu P, Tjian R, Skarnes WC and Wang Z

    Proceedings of the National Academy of Sciences of the United States of America 2008;105;18;6656-61

  • Notch, epidermal growth factor receptor, and beta1-integrin pathways are coordinated in neural stem cells.

    Campos LS, Decker L, Taylor V and Skarnes W

    The Journal of biological chemistry 2006;281;8;5300-9

  • Tectonic, a novel regulator of the Hedgehog pathway required for both activation and inhibition.

    Reiter JF and Skarnes WC

    Genes & development 2006;20;1;22-7

  • Polybromo protein BAF180 functions in mammalian cardiac chamber maturation.

    Wang Z, Zhai W, Richardson JA, Olson EN, Meneses JJ, Firpo MT, Kang C, Skarnes WC and Tjian R

    Genes & development 2004;18;24;3106-16

  • The Wnt co-receptors Lrp5 and Lrp6 are essential for gastrulation in mice.

    Kelly OG, Pinson KI and Skarnes WC

    Development (Cambridge, England) 2004;131;12;2803-15

  • Functional analysis of secreted and transmembrane proteins critical to mouse development.

    Mitchell KJ, Pinson KI, Kelly OG, Brennan J, Zupicich J, Scherz P, Leighton PA, Goodrich LV, Lu X, Avery BJ, Tate P, Dill K, Pangilinan E, Wakenight P, Tessier-Lavigne M and Skarnes WC

    Nature genetics 2001;28;3;241-9

  • An LDL-receptor-related protein mediates Wnt signalling in mice.

    Pinson KI, Brennan J, Monkley S, Avery BJ and Skarnes WC

    Nature 2000;407;6803;535-8

Team

No team members listed

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