Biology subjects

Bowling, S.

Publications and source records attributed to Bowling, S..

3 recordsLinked to original sources

bioRxiv2020

Differences in mitochondrial activity trigger cell competition during early mouse development.

Cell competition is emerging as a quality control mechanism that eliminates unfit cells in a wide range of settings from development to the adult. However, the nature of the cells normally eliminated by cell competition and what triggers their elimination remains poorly understood. In mouse, prior to gastrulation 35% of epiblast cells are eliminated. Here we have performed single cell transcriptional profiling of these cells and find that they show the hallmarks of cell competition and have mitochondrial defects. We demonstrate that mitochondrial defects are common to a range of different loser cell types and that manipulating mitochondrial function is sufficient to trigger competition. Importantly, we show that in the embryo cell competition eliminates cells with mitochondrial DNA mutations and that even non-pathological changes in mitochondrial DNA sequence can induce cell competition. Our results therefore suggest that cell competition is a purifying selection that optimises mitochondrial performance prior to gastrulation.

developmental biology↗

bioRxiv2019

DRP1-mediated regulation of mitochondrial dynamics determines the apoptotic response upon embryonic differentiation.

The changes that drive differentiation create a large potential for the emergence of abnormal cells that need to be removed before they contribute to further development or the germline. This removal is in part achieved by cells becoming hypersensitive to death upon exit of naive pluripotency. What causes this change in apoptotic response is unknown. Here we identify that it is controlled by the regulator of mitochondrial dynamics DRP1. We show that in mouse, naive pluripotent cells have fragmented mitochondria due to high DRP1-mediated fission, but upon differentiation, DRP1 activity decreases, inducing mitochondria to fuse and form complex networks. We demonstrate that this decrease in DRP1 activity lowers the apoptotic threshold, as mutation of DRP1 increases the sensitivity to cell death and its over-expression protects against apoptosis. Together, our findings highlight how regulation of mitochondrial dynamics allows cells to adapt their apoptotic response to the changing environment of differentiation.

developmental biology↗

bioRxiv2019

An engineered CRISPR/Cas9 mouse line for simultaneous readout of lineage histories and gene expression profiles in single cells

Tracing the lineage history of cells is key to answering diverse and fundamental questions in biology. Particularly in the context of stem cell biology, analysis of single cell lineages in their native state has elucidated novel fates and highlighted heterogeneity of function. Coupling of such ancestry information with other molecular readouts represents an important goal in the field. Here, we describe the CARLIN (for CRISPR Array Repair LINeage tracing) mouse line and corresponding analysis tools that can be used to simultaneously interrogate the lineage and transcriptomic information of single cells in vivo. This model exploits CRISPR technology to generate up to 44,000 transcribed barcodes in an inducible fashion at any point during development or adulthood, is compatible with sequential barcoding, and is fully genetically defined. We have used CARLIN to identify intrinsic biases in the activity of fetal liver hematopoietic stem cell (HSC) clones and to uncover a previously unappreciated clonal bottleneck in the response of HSCs to injury. CARLIN also allows the unbiased identification of transcriptional signatures based on in vivo stem cell function without a need for markers or cell sorting.

developmental biology↗