Association between the development of the body axis and the craniofacial skeleton studied by immunohistochemical analyses using collagen II, Pax9, Pax1, and Noggin antibodies.
METHODS
Immunohistochemical analyses on the axial skeleton from wild type mice.


OBJECTIVE
In the clinic, we have previously observed cervical spine defects associated with deviations in the posterior part of the occipital bone and with morphologic and functional variations in the craniofacial skeleton. As examples, cervical spine fusions occurred frequently in patients with mandibular overjet and even more frequently and more caudally in the cervical spine in patients with sleep apnoea. The aims of the present study were to elucidate this association between the spine and the cranium by comparing gene expression domains of important developmental genes known to be involved in vertebral column formation with gene expression in the craniofacial region.


BACKGROUND
This is the first study looking specifically on gene expression in the basilar part of the occipital bone that is formed around the cranial part of the notochord, thus connecting the spine and the craniofacial skeleton.


METHODS
The material consisted of 4 mouse embryos p.c. day 13.5, NMRI wild-type mice, from the same litter. The body axis, the cranial base, and the craniofacial area were studied by immunohistochemical analyses using Collagen II, Pax9, Pax1, and Noggin antibodies.


RESULTS
Pax1 expression was highly similar in the posterior part of the occipital bone and in the vertebral column, indicating that the basilar part of the occipital bone from a developmental standpoint can be considered the uppermost vertebra. Pax9 and Noggin expression domains were in accordance with those described previously.


CONCLUSIONS
The present study supports that the basilar part of the occipital bone may be regulated by similar developmental mechanisms as the vertebral column and may thus be regarded the uppermost vertebra. Thus, the clinically observed association between the cervical column and the craniofacial area has been proved by immunohistochemical methods.
Sonnesen
Liselotte
L
Department of Orthodontics, Institute of Odontology, Wilhelm Johannsen Centre for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark. LLS@odont.ku.dk
Nolting
Dorrit
D
Kjaer
Klaus Wilbrandt
KW
Kjaer
Inger
I
D000818:Animals; D019521:Body Patterning; D002352:Carrier Proteins / Q000494:pharmacology; D002574:Cervical Vertebrae / Q000196:embryology*; D024043:Collagen Type II / Q000494:pharmacology* / Q000502:physiology*; D005147:Facial Bones / Q000196:embryology*; D007150:Immunohistochemistry / Q000379:methods*; D051379:Mice; D009777:Occipital Bone / Q000196:embryology*; D051764:PAX9 Transcription Factor / Q000494:pharmacology; D051761:Paired Box Transcription Factors / Q000494:pharmacology; D000099176:Noggin Protein
D002352:Carrier Proteins; D024043:Collagen Type II; D051764:PAX9 Transcription Factor; D051761:Paired Box Transcription Factors; D000099176:Noggin Protein; C070835:PAX1 transcription factor