Specification of jaw subdivisions by Dlx genes.
The success of vertebrates was due in part to the acquisition and modification of jaws. Jaws are principally derived from the branchial arches, embryonic structures that exhibit proximodistal polarity. To investigate the mechanisms that specify the identity of skeletal elements within the arches, we examined mice lacking expression of Dlx5 and Dlx6, linked homeobox genes expressed distally but not proximally within the arches. Dlx5/6-/- mutants exhibit a homeotic transformation of lower jaws to upper jaws. We suggest that nested Dlx expression in the arches patterns their proximodistal axes. Evolutionary acquisition and subsequent refinement of jaws may have been dependent on modification of Dlx expression.
Nina Ireland Laboratory of Developmental Neurobiology, 401 Parnassus Avenue, University of California, San Francisco, San Francisco, CA 94143-0984, USA.
Michael J
MJ
Depew
Thomas
T
Lufkin
John L R
JL
Rubenstein
D000818:Animals; D005075:Biological Evolution; D019521:Body Patterning; D001934:Branchial Region / Q000196:embryology / Q000502:physiology; D004429:Ear Ossicles / Q000196:embryology; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology; D008334:Mandible / Q000033:anatomy & histology / Q000196:embryology*; D008437:Maxilla / Q000033:anatomy & histology / Q000196:embryology*; D051379:Mice; D009024:Morphogenesis; D010159:Palate / Q000196:embryology; D012886:Skull / Q000002:abnormalities / Q000196:embryology; D013100:Sphenoid Bone / Q000196:embryology
C501120:Dlx5 protein, mouse; C100597:Dlx6 protein, mouse; D018398:Homeodomain Proteins