Morphogenesis is the process in which an embryo and its organs are shaped and formed, and is accomplished through organization of groups of cells into compartments. Prior to morphogenesis, cells are programmed to follow a specific cell fate, yet once morphogenesis begins there is typically little plasticity in the identities of the cells. However, a recent paper shows the reprogramming of certain cells during late morphogenesis of the fruit fly Drosophila, dependent on the JNK signaling pathway this is common to many species. Image above is a developing fly embryo undergoing dorsal closure, a well-studied example of morphogenesis during which cells stretch and zip up the tissue. Yellow cells are the “mixer cells” identified as being reprogrammable and able to cross compartment boundaries, while red and green cells intercalate to take their place during (top) and after (bottom) dorsal closure.
Reference: Melanie Gettings, Fanny Serman, Raphaël Rousset, Patrizia Bagnerini, Luis Almeida, Stéphane Noselli. Authors’ PLoS Biology paper can be found here.