Cells lacking TSC1 (outlined) express Elav (blue) and Prospero (red) ahead of the differentiation front (dotted line).
MCNEILL/ELSEVIER
Insulin is the perfect candidate to decide when cells should differentiate, as it is a well-known growth regulator. Along with the Tor pathway, which senses amino acid levels, insulin turns up ribosome synthesis to match increased nutrient availability. Bateman and McNeill now find that insulin and Tor also control neuronal tissue differentiation. Whereas the identities of cell fates were unaffected by changes in insulin signaling, the fates were acquired at inappropriate times.
The aberrant timings were easily seen in the developing fly eye, whose 800 photoreceptor clusters differentiate in a wave pattern that makes timing mutants easy to identify. While...
