Expression of the dlx gene family during formation of the cranial bones in the zebrafish (Danio rerio): differential involvement in the visceral skeleton and braincase.
We have used dlx genes to test the hypothesis of a separate developmental program for dermal and cartilage bones within the neuro- and splanchnocranium by comparing expression patterns of all eight dlx genes during cranial bone formation in zebrafish from 1 day postfertilization (dPF) to 15 dPF. dlx genes are expressed in the visceral skeleton but not during the formation of dermal or cartilage bones of the braincase. The spatiotemporal expression pattern of all the members of the dlx gene family, support the view that dlx genes impart cellular identity to the different arches, required to make arch-specific dermal bones. Expression patterns seemingly associated with cartilage (perichondral) bones of the arches, in contrast, are probably related to ongoing differentiation of the underlying cartilage rather than with differentiation of perichondral bones themselves. Whether dlx genes originally functioned in the visceral skeleton only, and whether their involvement in the formation of neurocranial bones (as in mammals) is secondary, awaits clarification.
Ghent University, Biology Department, Ghent, Belgium.
L
L
Verreijdt
M
M
Debiais-Thibaud
V
V
Borday-Birraux
C
C
Van der Heyden
J-Y
JY
Sire
A
A
Huysseune
D000818:Animals; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics*; D005810:Multigene Family; D010012:Osteogenesis / Q000235:genetics; D012886:Skull / Q000196:embryology* / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D015027:Zebrafish / Q000196:embryology* / Q000378:metabolism / Q000502:physiology; D029961:Zebrafish Proteins / Q000096:biosynthesis / Q000235:genetics
C088334:Distal-less homeobox proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C498152:dlx3b protein, zebrafish; C501122:dlx5a protein, zebrafish