4. Cell Migration in Making Tissues: you lost, then you die.
Cell migration is a very influential process during embryonic development as it results in rearrangement of cells from one part of the embryo to another, effectively controlling cell-cell interactions to drive cell differentiation and organogenesis. The shape of most complex organ systems arises from the directed migration of cohesive groups of cells. Therefore, cell migration must be regulated temporally and spatially for organisms to develop properly. The overlying goal of our research objective is to provide insight into how cells within a migrating groups sense their environment and how this contributes to their collective movement. We study the movement of mesoderm cells during gastrulation (see Sun and Stathopoulos, Dev 2018) and at later stages mesoderm cells which are precursors of longitudinal muscles (see Macabenta and Stathopoulos, Dev 2019). Caudal visceral mesoderm (CVM) cells exhibit directed cell migration as two distinct groups on either side of the body, from the posterior-most position of the embryo toward the anterior. The cells undergo the longest migration in all of Drosophila embryogenesis, but little is understood about how they are directed along their course. The migration ensues over six hours and is necessary to position CVM cells along the entire length of the developing gut. At the end of their migration, CVM cells fuse with fusion-competent myoblasts to form the longitudinal muscles which ensheath the gut. Curiously, if these migrating cells move off track they undergo apoptosis. We are interested in understanding the signals that guide migration of cells as well as the mechanism by which cells off-track are killed off.