Precision patterning: How inner hair cells "hop" to it

Abstract

A combination of Notch-mediated lateral inhibition, mechanical forces, and differential adhesion generates a single row of alternating inner hair and supporting cells.

Fig. 1.. Cell pattern formation in the human cochlea.

Left: (A) Notch-mediated lateral inhibition drives formation of inner hair cells (magenta) and supporting cells (green), bordered by a single row of inner pillar cells (blue). Outer hair cells are not shown. (B) Pressure on the forming epithelium drives cellular intercalations (I) and hopping intercalations (H). (C) Hair cells not contacting pillar cells delaminate (D) and disappear. (D) Preferred adhesion between different cell types straightens out cell alignments. Right: A side view of hopping intercalation: Inner hair cells move toward and contact inner pillar cells basolaterally, forming a junction labeled by Z01-GFP (yellow). The junction moves up the surface of the inner pillar, until it forms a new apical footprint that merges with the original, juxtaposing the hair and inner pillar cells. Note that hair cells are detached from the basement membrane and hence malleable to basolateral displacement. Credit: Jemma Webber.