The role of NF-κB in early development

In vivo studies using the mouse embryo has allowed us to dissect many cell-fate decisions that lead to defined cell and tissue identities, however at this stage of development, embryos are difficult to manipulate, expensive, and require large numbers of animals to ensure proper statistical power. Embryonic stem (ES) cells, offer a useful and tractable alternative model to study cell fate decision- making due to their unlimited capacity for self-renewal, and their ability to differentiate into all tissues and lineages of the embryo proper. This approach simplifies the experimental system, and has the potential to provide a more nuanced understanding of how key cell-fate decisions are modulated during early development.

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Recent work has suggested that the balance between differentiation and pluripotency in ES cells is modulated by members of the heterodimeric Nuclear Factor kappaB (NF-κB) family. These transcription factors are critical in determining cell fate in a number of contexts (inflammation, immunity etc.), yet its role in early mammalian development is highly controversial, and poorly defined. Furthermore, an important, and oft-overlooked characteristic of NF-κB signalling is its intracellular dynamics. Following activation, its localisation oscillates between the nucleus and cytoplasm, the oscillatory frequency encoding specific transcriptional programs, intricately linking dynamic activity to cell fate. As of yet, only bulk-cell assays or fixed samples have been used to study the role of NF-κB during ES cell multilineage differentiation. Consequently, there has been no attempt to understand whether the dynamics of NF-κB facilitate or control the cell-fate decisions that lead to the exit from pluripotency towards a defined embryonic lineage.

We're taking a combinatorial approach combining bulk-cell biochemical analysis, single-cell immunofluorescence and live-cell imaging to define the role of NF-κB in cell fate decisions during early mammalian lineage commitment.