A clone from a single cortical progenitor contains both early-born (green) and later-born (red) neurons.
SHEN/ELSEVIER
Cortical neurons are born in strict order: subtypes born earliest form layer one and the subplate; consecutively later-born subtypes construct the six cortical layers from the bottom up. The researchers now show that vertebrate neural progenitors maintain this order without extrinsic cues. “In vitro recapitulation of normal timing suggests that there is an internal program,” says Shen.
The internal controller seems to be the Foxg1 transcription factor, which was previously linked to the control of timing in neurogenesis. When the researchers knocked down Foxg1, older progenitors reacquired their ability to make younger subtypes. The lab is now looking for...
