Notch Role In Lateral Inhibition

In Drosophila:

Lateral inhibition by Delta-Notch signalling is used to determine which cell within a proneural cluster will go on to become a neuroblast by inhibition of adjacent cells.

Initially, within proneural clusters in the neurectoderm, all cells are capable of becoming neural precursor cells. An autocrine signal from one cell then promotes its own development to become a neuroblast, at the same time signalling to neighbouring cells to prevent them from acquiring this fate.

This neuroblast expresses proneural genes e.g. Achaete, while surrounding cells become epidermis.

(Self made image: Shows the formation of neuroblasts from equilavence groups.)

Role of Delta-Notch in this lateral inhibition?

All cells in the proneural cluster initially express Delta and Notch. The prospective neuroblast begins to express Delta more strongly than others, this interacts with Notch on neighbouring cells. Increased Notch stimulation in adjacent cells leads to feedback pathways involving transcription factors Enhancer-Of-Split and Suppressor-of-hairless. These factors act to repress production of proneural genes such as Achaete and Schute as well as Delta in surrounding cells. Surrounding cells are therefore inhibited from becoming neural fate and instead become epidermis.

The resulting neuroblasts enlarge and move to the interior of the embryo where they will give rise to neurons and their supporting cells (glial cells)

(Self Made image)

Reference: Information from: Principles Of Development Fourth Edition. Lewis Wolpert, Cheryll Tickle et al. Pg. 470-475.