Proper connectivity of Drosophila motion detector neurons requires Atonal function in progenitor cells.

BACKGROUND: Vertebrates and invertebrates obtain visual motion information by channeling moving visual cues perceived by the retina through specific motion sensitive synaptic relays in the brain. In Drosophila, the series of synaptic relays forming the optic lobe are known as the lamina, medulla, lobula and lobula plate neuropiles. The fly's motion detection output neurons, called the T4 and T5 cells, reside in the lobula plate. Adult optic lobe neurons are derived from larval neural progenitors in two proliferating compartments known as the outer and inner proliferation centers (OPC and IPC). Important insight has been gained into molecular mechanisms involved in the development of the lamina and medulla from the OPC, though less is known about the development of the lobula and lobula plate. RESULTS: Here we show that the proneural gene Atonal is expressed in a subset of IPC progenitors that give rise to the higher order motion detection neurons, T4 and T5, of the lobula plate. We also show that Atonal does not act as a proneural gene in this context. Rather, it is required specifically in IPC neural progenitors to regulate neurite outgrowth in the neuronal progeny. CONCLUSIONS: Our findings reveal that a proneural gene is expressed in progenitors but is required for neurite development of their progeny neurons. This suggests that transcriptional programs initiated specifically in progenitors are necessary for subsequent neuronal morphogenesis.

Unraveling the protective effect of a Drosophila phosphatidylethanolamine-binding protein upon bacterial infection by means of proteomics.

This study addresses the biological function of CG18594, a Drosophila melanogaster phosphatidylethanolamine-binding protein (PEBP) that we named PEBP1, by combining fly genetics, survival experiments and differential proteomics. We demonstrate that transgenic flies overexpressing PEBP1 are highly protected against bacterial infection due to the release of immunity-related proteins in their hemolymph. Apart from proteins that have been reported earlier to participate in insect immunity, we also identify proteins involved in metabolism and signaling, and, in addition, twelve (hypothetical) proteins with unknown function. This is the first report demonstrating an immune function for a Drosophila PEBP protein.