Data from: Transcriptional response of Hoxb genes to retinoid signalling is regionally restricted along the neural tube rostrocaudal axis

During vertebrate neural development, positional information is
largely specified by extra-cellular morphogens. Their distribution,
however, is very dynamic due to the multiple roles played by the same
signals in the developing and adult neural tissue. This suggests that
neural progenitors are able to modify their competence to respond to
morphogen signalling and autonomously maintain positional identities after
their initial specification. In this work, we take advantage of in vitro
culture systems of mouse neural stem/progenitor cells (NSPCs) to show that
NSPCs isolated from rostral or caudal regions of the mouse neural tube are
differentially responsive to retinoic acid (RA), a pivotal morphogen for
the specification of posterior neural fates. Hoxb genes are among the best
known RA direct targets in the neural tissue, yet we found that RA could
promote their transcription only in caudal, but not in rostral NSPCs.
Correlating with these effects, key RA-responsive regulatory regions in the
Hoxb cluster displayed opposite enrichment of activating or repressing
histone marks in rostral and caudal NSPCs. Finally, RA was able to
strengthen Hoxb chromatin activation in caudal NSPCs, but was ineffective
on the repressed Hoxb chromatin of rostral NSPCs. These results suggest
that the response of NSPCs to morphogen signalling across the rostrocaudal
axis of the neural tube is gated by the epigenetic configuration of target
patterning genes, allowing long-term maintenance of intrinsic positional
values in spite of continuously changing extrinsic signals.