Variations of cervical vertebrae after expression of a Hox-1.1 transgene in mice.
To understand the function of murine homeobox genes, a genetic analysis is mandatory. We generated gain-of-function mutants by introducing genomic sequences of the Hox-1.1 gene under the control of a chicken beta-actin promoter into mice. Our previous data had shown that these transgenic mice are nonviable after birth and are born with craniofacial abnormalities. In a subsequent detailed analysis of severely affected animals, malformations of the basioccipital bone, the atlas, and the axis were observed. Manifestation of an additional vertebra, a proatlas, occurred at the craniocervical transition. The dominant interference of the Hox-1.1 transgene with developmental programs seems to occur around day 9 of gestation, the time of neural crest migration and somite differentiation. We discuss the resulting phenotype with respect to a developmental control function of Hox-1.1.
Kessel
M
M
Department of Molecular Cell Biology, Max Planck Institute of Biophysical Chemistry, Göttingen, Federal Republic of Germany.
Balling
R
R
Gruss
P
P
D000818:Animals; D000831:Animals, Newborn; D002574:Cervical Vertebrae / Q000002:abnormalities* / Q000033:anatomy & histology / Q000473:pathology; D005801:Genes, Homeobox; D005822:Genetic Vectors; D051379:Mice; D008822:Mice, Transgenic; D010641:Phenotype