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- 6 rows of cells secret denticles while the remaining cells make bald
cuticle
- patterning occurs progressively from the deployment of coarsely expressed
gap genes to the more refined segment polarity genes (reviewed by Ingham,
1988)
- bald fate arises b/c shavenbaby
- veinlet contributes to the formation of denticle types 1-4 (Wiellete
et al., 1999)
- Spitz proposed to specify different denticle types in a concentration-dependent
manner
- mutants in Serrate, a gene that encodes a Notch ligand, have denticle
defects
- Serrate expressed within prospective denticle belts, in a pattern
that does not overlap with that of veinlet expression (Wiellette et
al., 1999)
- 4 molecules activating 4 signaling pathways (Wg, Hh, Egfr, and Notch)
are expressed in a precise spatial pattern within an 8-cell-wide band
(Alexandre,
1999)
- Hh has diffenrential quantitative effects across three cell diameters
(Alexandre,
1999)
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