Project name: Mus musculus

Description: Hox and Cdx transcription factors regulate embryonic positional identities. Cdx mutant mice display posterior body truncations of the axial skeleton, neuraxis, and caudal uro-rectal structures. We show that trunk Hox genes stimulate axial extension as they can largely rescue these Cdx mutant phenotypes. Conversely, posterior (paralog group 13) Hox genes can prematurely arrest posterior axial growth when precociously expressed. Our data suggest that the transition from trunk to tail Hox gene expression successively regulates construction and termination of axial structures in the mouse embryo. Thus, Hox genes seem to differentially orchestrate posterior expansion of embryonic tissues during axial morphogenesis as an integral part of their function in specifying head-to-tail identity. In addition, we present evidence that Cdx and Hox transcription factors exert these effects by controlling Wnt signaling. Concomitant regulation of Cyp26a1 expression, restraining retinoic acid signaling in the posterior growth zone, may likewise play a role in timing the trunk-tail transition.Overall design: A micro-array screen of down regulated and upregulated genes in Cdx2+/-Cdx4-/- mutant embryos versus wildtype embryos was performed at the embryonic stage of 13 somites. RNA was isolated from the posterior part of the embryos dissected at the same axial level using the last somite boundary as a landmark. Posterior tissues from pools of 7 embryos of each genotype were pooled. The labeled cRNAs were hybridized on 4X44K Agilent Whole Mouse Genome dual colour Microarrays (G4122F) in a dye swap experiment, resulting in two individual microarrays.

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: ModelOrganism

Last updated: 2009-08-14