Extrinsic activin signaling cooperates with an intrinsic temporal program to increase mushroom body neuronal diversity

• Published in: eLife Vol. 9
• Main Authors: Rossi, Anthony M, Desplan, Claude
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 06.07.2020; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Activin; Activins - metabolism; Animals; Binding proteins; Cloning; Developmental Biology; Drosophila; Drosophila melanogaster - genetics; Drosophila melanogaster - physiology; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Insects; kenyon cells; Ligands; Missing persons; Mushroom Bodies - physiology; mushroom body; myoglianin; Neural stem cells; Neural Stem Cells - physiology; Neuroblasts; Neuronal-glial interactions; Neurons; Neurons - physiology; Neuroscience; O'Connor, Michael; Pattern formation; Protein binding; Ribonucleic acid; RNA; RNA-binding protein; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Signal Transduction; temporal patterning; Transforming Growth Factor beta - genetics; Transforming Growth Factor beta - metabolism; Canada; myoglianin; activin; Drosophila; developmental biology; neuroscience; mushroom body; temporal patterning; kenyon cells; D. melanogaster
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.58880

Temporal patterning of neural progenitors leads to the sequential production of diverse neurons. To understand how extrinsic cues influence intrinsic temporal programs, we studied mushroom body progenitors (neuroblasts) that sequentially produce only three neuronal types: γ, then α'β', followed by αβ. Opposing gradients of two RNA-binding proteins Imp and Syp comprise the intrinsic temporal program. Extrinsic activin signaling regulates the production of α'β' neurons but whether it affects the intrinsic temporal program was not known. We show that the activin ligand Myoglianin from glia regulates the temporal factor Imp in mushroom body neuroblasts. Neuroblasts missing the activin receptor Baboon have a delayed intrinsic program as Imp is higher than normal during the α'β' temporal window, causing the loss of α'β' neurons, a decrease in αβ neurons, and a likely increase in γ neurons, without affecting the overall number of neurons produced. Our results illustrate that an extrinsic cue modifies an intrinsic temporal program to increase neuronal diversity.