On day 140 of #LMB365 we have a picture by Katja Röper in the Cell biology Division. This image shows a confocal section of a mouse lung bud at embryonic day 12. Nuclei of cells are labelled in blue, the microtubule cytoskeleton in green and cell-cell junctions in red. The Röper lab studies how important tubular organs such as the lung form during development.