Development of the spatial pattern of retinoic acid receptor-beta transcripts in embryonic chick facial primordia.
Retinoic acid causes a range of embryonic defects, including craniofacial abnormalities, in both birds and mammals and is believed to have a number of roles in normal development. We have previously shown that the distribution of retinoic acid receptor-beta (RAR-beta) transcripts is spatially restricted within the neural-crest-derived upper beak primordia of the chick embryo. We have now used in situ hybridisation to trace the distribution of RAR-beta transcripts during the migration of cranial neural crest cells and during formation of these primordia. RAR-beta transcripts were present in a subset of migrating neural-crest-derived cells in the head of the stage 10 embryo. These cells were situated in pathways followed by cells that migrate from the neural crest overlying the posterior prosencephalic/anterior mesencephalic region of the developing brain. Cells containing RAR-beta transcripts accumulated around the developing eyes and in the regions of the ventral head from which the upper beak primordia later develop. We mapped the distribution of RAR-beta transcripts as the facial primordia were forming, with particular reference to the development of the maxillary primordia. We found that these form in a region of the ventral head that includes the boundary between regions of high and low levels of RAR-beta transcripts. The boundary between these two groups of cells persisted as the maxillary primordia developed.(ABSTRACT TRUNCATED AT 250 WORDS)
Rowe
A
A
Department of Anatomy and Developmental Biology, University College and Middlesex School of Medicine, UK.
Richman
J M
JM
Brickell
P M
PM
D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D002642:Chick Embryo; D005145:Face / Q000196:embryology*; D008445:Maxillofacial Development / Q000235:genetics*; D015336:Molecular Probe Techniques; D009024:Morphogenesis / Q000235:genetics; D009432:Neural Crest / Q000502:physiology*; D018168:Receptors, Retinoic Acid; D014212:Tretinoin / Q000378:metabolism*
D002352:Carrier Proteins; D018168:Receptors, Retinoic Acid; D014212:Tretinoin