Additional enhancer copies, with intact cdx binding sites, anteriorize Hoxa-7/lacZ expression in mouse embryos: evidence in keeping with an instructional cdx gradient.

Expression of a Hoxa-7/lacZ reporter construct in transgenic mouse embryos is shifted anteriorly when the upstream enhancer is multimerized. The shift occurs in spinal ganglia, neurectoderm and in both paraxial and lateral plate mesoderms. Much of the multimer effect is inhibited by destruction of a single caudal (cdx) binding motif in the additional copies of the enhancer.

Vertebrate caudal gene expression gradients investigated by use of chick cdx-A/lacZ and mouse cdx-1/lacZ reporters in transgenic mouse embryos: evidence for an intron enhancer.

The vertebrate caudal proteins, being upstream regulators of the Hox genes, play a role in establishment of the body plan. We describe analysis of two orthologous caudal genes (chick cdx-A and mouse cdx-1) by use of lacZ reporters expressed in transgenic mouse embryos. The expression patterns show many similarities to the expression of endogenous mouse cdx-1.