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Figure 2 | Molecular Brain

Figure 2

From: Molecular mechanisms of tiling and self-avoidance in neural development

Figure 2

Proposed models for the action of Drosophila and vertebrate Dscams. A, Drosophila Dscam1 mediates homotypic repulsion in tiling and self-avoidance. The homophilic binding specificity of Dscam1 is determined by its Ig2 (red), Ig3 (green) and Ig7 (purple) domains. Half of Ig2, half of Ig3, and entire Ig7 domains are encoded by one of 12, 48, and 33 alternative exons, respectively. Thus, the extensive alternative splicing can generate 19,008 Dscam1 isoforms with different binding specificity. The binding between two Dscam isoforms only occurs if all three Ig domains (i.e. Ig2, Ig3 and Ig7) are identical. B, Vertebrate Dscams may mediate de-adhesion in tiling and self-avoidance by down-regulating the function of some unknown cell-type-specific adhesion molecules. The binding region on vertebrate Dscams is unknown, and presumably contains one or more of Ig domains. Circles, Ig domains. Rectangles, fibronectin type-III repeats. PM, plasma membrane

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