“…The Drosophila JAK/STAT signaling pathway is composed of several major factors: the three ligands Unpaired (Upd) (Harrison et al, 1998), Upd2 (Gilbert et al, 2005;Hombria et al, 2005) and Upd3 (Agaisse et al, 2003); the transmembrane receptor Domeless (Dome) (Brown et al, 2001;Chen et al, 2002); the JAK homolog Hopscotch (Hop) (Binari and Perrimon, 1994); and the STAT homolog Stat92E (Hou et al, 1996;Yan et al, 1996). JAK/STAT signaling is involved in many developmental processes, including segmentation in embryogenesis, eye morphogenesis, hematopoiesis and stem cell maintenance (Arbouzova and Zeidler, 2006;Luo and Dearolf, 2001;Zeidler et al, 2000). Here, we report a novel mechanism underlying NB (neural progenitor) formation and discuss its role in establishing a precise topographic map in the visual system.…”