Haematopoesis and Immunity
Haematopoiesis involves commitment of a common progenitor, proliferation and differentiation into several specialised blood cell types that participate to a wide range of function such as host defence against infection and haemostasis. Up-regulation of the haematopoietic system plays a critical role in establishing the proper response against invading pathogens, in removing cancerous cells or in tissue remodelling during normal development. Furthermore, deregulations of the haematopoietic differentiation program are at the origin of numerous diseases including leukaemia and lymphoma. Unravelling the genetic circuitry and the molecular mechanisms that control normal and pathological blood cell formation and differentiation is a major challenge. Recent evidence has shown that several features of haematopoietic development are conserved from Drosophila to vertebrates. Thus Drosophila might provide a powerful system in which to characterise the basic molecular genetic mechanisms controlling haematopoiesis.
We have started to address the molecular mechanisms of action of the GATA factor Serpent (Srp) during embryonic blood cell formation. It appears that Srp is a key player at different stages of haematopoiesis and that the cross-regulatory interactions between Srp, the RUNX factor Lozenge (Lz) and the FOG factor U-shaped (Ush) might constitute a conserved means of regulating lineage choice and differentiation.