Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.24.219469v1?rss=1 Authors: Ishii, M., Tateya, T., Matsuda, M., Hirashima, T. Abstract: A notable example of spiral architecture in organs is the mammalian cochlear duct, where the morphology is critical for hearing function. Molecular genetics has revealed the necessary signaling molecules, but it remains unclear how cellular dynamics generate bending and coiling of the cochlear duct. Here we show two modes of multicellular dynamics underlying the morphogenetic process by deep tissue live-cell imaging and mathematical modeling. First, surgical separation revealed that bending forces reside primarily in the medial side of the duct. In the medial pseudostratified epithelium, we found that nuclei stall at the luminal side after cell division, which would cause bending of the duct. Second, long-term FRET imaging showed that helical ERK activation waves propagate from the duct tip concomitant with the reverse multicellular flow in the lateral side of the duct, resulting in advection-based duct elongation. We propose an interplay of distinct multicellular behaviors underpinning the cochlear duct morphogenesis. Copy rights belong to original authors. Visit the link for more info