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Biology subjects

Agsu, G. G.

Publications and source records attributed to Agsu, G. G..

2 recordsLinked to original sources

Organoids reveal niche-specific mechanotransduction-guided human cortical patterning and cell fate acquisition

The highly dynamic mechanical environment of the developing cerebral cortex has the potential to encode information vital for neuronal differentiation. Changes in local biophysical properties have been implicated in processes ranging from the maintenance of neural progenitors to long-range axon guidance. However, whether cortical mechanics influence cellular organisation and specification during neurogenesis remains largely unexplored. Here, we leverage a 3D mosaic organoid model of human cortical development, in which we selectively disrupt a key component of nuclear mechanosensing, the LINC complex, decoupling cells from their mechanical environment. We show that LINC-decoupling alters nuclear morphology in a compartment-specific manner, driving preferential exclusion from the germinal zone and concomitant premature differentiation. Excluded cells exhibit a biased spatial distribution in the cortical plate and altered fate allocation, with loss of intermediate progenitors and upper-layer neuron populations. Combining this approach with single-cell transcriptomic profiling, we reveal a signature of impaired ERK activation and density sensing in LINC-decoupled cells. Furthermore, we show that altered density sensing contributes to mislocalisation of the nuclear envelope protein emerin and disruption of histone mark deposition during differentiation. Taken together, our findings illustrate how the dynamic mechanical environment of a complex tissue can dictate cell fate and pattern formation during development.

developmental biology↗

Protein-protein interactions drive differences in the spatiotemporal dynamics of transcription factors NANOG and SOX2 in naïve pluripotent cells

Maintenance of naive pluripotency requires core transcription factors (TFs) like SOX2 and auxiliary TFs like NANOG, yet molecular mechanisms governing their intra-nuclear dynamics and DNA binding interactions remain unclear. Here, using high-density 3D single-molecule light-field microscopy combined with novel spatiotemporal analysis pipelines, we track SOX2 and NANOG dynamics in live cells. Despite lower protein abundance, NANOG displays a similar chromatin-bound fraction to SOX2. This arises partially because, while both TFs undergo frequent transient non-specific binding interactions ([~]0.5-0.7s), NANOG exhibits more stable specific binding ([~]25s vs [~]16s). Both TFs also assemble into phase-separated domains of [~]400 nm containing both freely diffusing and chromatin-bound proteins, which further influences their dynamics. Strikingly, NANOGs protein-protein interaction domain markedly increases chromatin residence time (>5-fold) and the size of these phase-separated domains. Our work uncovers how NANOG and SOX2 stabilise gene regulatory networks that maintain naive pluripotency while providing quantitative pipelines for dissecting spatiotemporal TF dynamics.

cell biology↗