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Baby Gap

Understanding more about the protein transport route via junctions between cells

16 May 2021

Baby Gap

Life is full of give and take – cells and tissues exchange chemicals with each other, often pushing them through tiny channels in cell membranes. There is another way though, making use of the gaps where cells meet in the epithelium – the skin-like barrier that coats many of our tissues – but what controls this paracellular transport is a little mysterious. Here a mesh of epithelial cells (purple) nestles a developing egg cell in a fruit fly ovary. Pictured under a confocal fluorescence microscope, the cells form triangular junctions that expand or contract to create temporary intercellular spaces (green), long enough for yolk-forming proteins to squeeze through to the egg. With a similar mechanism helping chemicals move from the blood into mammalian testes, future work may unravel the role of paracellular transport in human fertility and development too.

Written by John Ankers

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BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

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