Dorsal closure and convergent extension: two polarised morphogenetic movements controlled by similar mechanisms?

Coordinated cell movements contribute to the shaping of developing organisms during morphogenesis. Understanding the molecular basis of these directed movements is a crucial part of understanding the mechanisms in action during development. We present here a cellular description of two morphogenetic processes: dorsal closure of the Drosophila embryo and convergent extension in two vertebrate models, Xenopus laevis and Danio rerio. Both processes are characterised by polarised cell movements and increasing evidence suggests that they involve a common group of planar cell polarity genes. We propose that the comparison of dorsal closure and convergent extension will shed light on underlying mechanisms that are shared between the two processes.