The role of ephrin-eph receptor signaling during enteric nervous system formation in manduca sexta

This thesis investigates the molecular mechanisms that guide neuronal migration, focusing on Eph receptor–Ephrin signaling in the developing enteric nervous system (ENS) of the moth Manduca sexta. Unlike vertebrate systems, where multiple Eph/Ephrin pairs complicate functional analysis, Manduca expresses only one class‑A Ephrin (MsEphrin) in migrating enteric neurons (EP cells) and one Eph receptor (MsEph) in midline regions that normally repel migration. Using tagged fusion proteins and antisense Morpholino knockdown, I demonstrate that MsEphrin–MsEph interactions mediate repulsive signaling that prevents EP cells from crossing the midline and restricts their movement to muscle band pathways. These findings identify a simple, tractable model of Ephrin‑Eph–dependent repulsive guidance and reveal a novel mechanism through which these cues regulate neuronal migration during ENS development.