The limb/LPM enhancer of the murine Hoxb6 gene: reporter gene analysis in transgenic embryos and studies of DNA-protein interactions

Abstract

Homeobox genes are expressed in stage-, region-, and tissue-specific patterns during embryonic development of the mouse. In order to study cis-acting regulatory elements of murine homeobox genes, transgenic mouse embryos were generated which contained the LacZ reporter gene under the control of different fragments from the murine Hoxb6 gene. A 2 kb limb/LPM (lateral plate mesoderm) enhancer region was identified which reproduced several aspects of the endogenous Hoxb6 gene expression pattern in the mesenchyme of the developing limb buds and the ventro-lateral body region. Both tissues represent derivatives of the lateral plate mesoderm. In order to describe proteins interacting with specific DNA sequences in the limb/LPM enhancer, electro mobility shift assays were performed using nuclear extracts prepared from embryonic tissues. Several specific DNA-protein complexes could be detected, suggesting that these DNA-protein interactions are important for the regulation of Hoxb6 gene expression.