As an embryo grows and transforms, its cells divide, shift, and take on new identities. Jennifer Zallen is studying the coordinated cell movements that shape the emerging animal form. She studies how large populations of young cells reorganize to become the elongated beginnings of a body, a transition that requires hundreds of cells to align their movements along a common axis.
Working on the fruit fly, her research team discovered that cells at this early stage form pinwheel-shaped rosettes, in which groups of cells line up and then rapidly reorganize themselves to create distance between the fly's future head and tail. This process involves coordinated contractile structures that extend across multiple cells, contracting and pulling the cluster into a rosette. This rosette mechanism has now been shown to be a fundamental strategy for tissue elongation that is conserved from flies to mammals.
In addition, Zallen's team has identified a molecular code that systematically orients cell movements throughout the embryo and orchestrates this dramatic shape change. This work, unraveling the molecular signals and biophysical forces that shape developing embryos, is an important foundation for understanding how errors in these processes lead to birth defects, kidney disease, and cancer.