Background

Epithelial tissues are composed of polarised cells with a belt of adherens junctions positioned between distinct apical and basolateral plasma membrane domains. How epithelial polarity is propagated through the cell cycle from mother to daughter cells remains unclear.

Method

Here we primarily use time-lapse imaging of the developing Drosophila wing epithelium to investigate the dynamics of epithelial polarity determinants through mitosis.

Results

We find that the localisation of several key polarity determinants is not maintained during cell division. As an epithelial cell enters mitosis, there is a transient disruption in the localisation of the adherens junction proteins Armadillo/beta-catenin and E-cadherin as well as the basolateral determinant Lethal Giant Larvae. Following cytokinesis, the localisation of these determinants is rapidly re-established to prevent extrusion from the epithelium. Re-establishment of polarity appears to depend on information from quiescent neighbouring cells, because forcing groups of epithelial cells to divide promotes collective loss of epithelial polarity and extrusion from the epithelium.

Conclusion

Our results suggest a principle that may underlie the tendency of dividing cancer cells to escape the epithelium during tumour progression.