Abstract
In any organism, the construction of the Central Nervous System (CNS) is a complex process that must comply with precise architectural rules. How it is attained and how it affects neural functionality are key issues to solve. In the Drosophila Ventral Nerve Cord (VNC), we uncovered a set of novel robust architectural elements (3D nodes) arranged in a precise pattern responding to a delicate balance on Jun-N-terminal kinase (JNK) signaling activity in specific pioneer neurons. This cascade controls axons and dendrites integrity and, non-autonomously, Fasciclin 2 (Fas 2) expression. A deficit in Fas 2 impairs the VNC architecture and condensation. Remarkably, the coordination of the embryonic motor activity essential for embryo hatching also responds to JNK activity in the same cells. Altogether, our data point to the JNK pathway as an essential element underpinning VNC robustness and reveal critical links between the architecture of the VNC and its functional optimization.