Intron of the mouse Hoxa-7 gene contains conserved homeodomain binding sites that can functionas an enhancer element in Drosophila

Intron of the mouse Hoxa-7 gene contains conserved homeodomain binding sites that can functionas an enhancer element in Drosophila

Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland

Abstract

The 5′ flanking sequences and the intron of the mouse Hoxa-7 gene were searched for regulatory elements that can function in Drosophila. Only the intron is able to activate a lacZ fusion gene in various tissues of Drosophila embryos. This enhancer function requires a cluster of three homeodomain binding sites (HB1-element) that are also found in the introns of other Hox genes as well as in a putative autoregulatory element of Ultrabithorax (Ubx), the Drosophila homolog of Hoxa-7. If a single binding site in the autoregulatory element of fushi tarazu (ftz) is replaced by the HB1-element of Hoxa-7, the expression pattern is altered and newly controlled by the homeotic gene caudal (cad). These data suggest that HB1 is a potential target for different homeodomain proteins of both vertebrates and invertebrates.

Footnotes

↵ * Present address: Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92717.
↵ † To whom reprint requests should be addressed.
Walter J. Gehring
Abbreviations: β-gal, β-galactosidase; HB1-element, homeodomain binding sites.