Vascular control of the Drosophila haematopoietic microenvironment by Slit/Robo signalling

The posterior signalling centre (PSC) in Drosophila larva regulates blood cell differentiation but it is unclear how this is controlled. Here, the authors show that Slit/Robo signalling from the vascular system regulates PSC morphology and function, in turn, regulating blood cell differentiation.