Pax3 and Pax7 play essential safeguard functions against environmental stress-induced birth defects

ABSTRACT: Exposure to environmental teratogenic pollutant leads to severe birth defects. However, the biological events underlying these developmental abnormalities remain undefined. Here we report a molecular link between an environmental stress response pathway and key developmental genes during craniofacial development. In our study, we focused on the development of the facial prominences at E11.5. To do so, we compared the transcriptomes of mutant embryos (*Pax3Pax3-ERD/GFP *called DM in the microarray samples) to the one of control embryos (*Pax3GFP/+ *called GFP in the sample names). These are knock-in genetic models described in Bajard et al., 2006 and Relaix et al., 2005. In both of them a cassette coding for the GFP is replacing one allele of the Pax3 gene. The Pax3-ERD allele is a conditional one that drives the expression of the dominant negative form of Pax3 (Pax3-ERD) composed of the Pax3 DNA binding domain fused to the engrailed repressor domain (ERD) upon activation of a Cre recombinase. In this study, the Cre was driven by the zygote specific PGK enhancer. Strikingly, mutant mice with impaired Pax3/7 function display severe craniofacial defects. We show these are associated with an up-regulation of the signaling pathway mediated by the Aryl hydrocarbon Receptor (AhR), the receptor to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), revealing a genetic interaction between Pax3 and AhR signaling. Activation of AhR signaling in Pax3-deficient embryos drives facial mesenchymal cells out of the cell cycle through the up-regulation of p21 expression. Accordingly, inhibiting AhR activity rescues the cycling status of these cells and the facial closure of Pax3/7 mutants. Together, our findings demonstrate that the regulation of AhR signaling by Pax3/7 is required to protect against TCDD/AhR-mediated teratogenesis during craniofacial development.

ORGANISM(S): Mus musculus

SUBMITTER: Antoine Zalc 

PROVIDER: E-MTAB-3238 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress