Germ cell motility clock

Organ development relies on interactions among different cell types that form three-dimensional structures to carry out specific tasks. This process often involves active migration of progenitor cells toward specific positions within the embryo, where the cells then become immotile and form stable connections among each other and with neighboring cell types. Yet, surprisingly little is known about processes of motility loss and the emerging organization of the cells at the site where the organ forms. In this work, we study these the process of motility loss processes using zebrafish primordial germ cells as an in vivo model. We show that changes in embryonic tissues as well as cell-autonomous events regulate germ cells' behavior as they arrive at their target region. Importantly, we find that reduction in germ cell motility is correlated with the decay of RNA encoding for Dead end 1 (Dnd1), a conserved vertebrate RNA-binding protein that is essential for PGC migration. Indeed, decreasing or increasing the level of Dnd1 results in a premature or delayed stop to motility, respectively. These findings represent a novel RNA decay-based mechanism for timing the duration of cell migration in vivo. Overall design: RNA-seq profiling of the zebrafish primordial germ cells (PGCs) positioned at the gonad region (wild-type condition) and at ectopic sites (ody mutant condition) at 2 developmental stages (24 and 36 hpf)