Control elements of the P2 promoter of the Antennapedia gene.

Antennapedia (Antp), a homeotic gene of Drosophila required for proper differentiation of the thorax of the fly, is expressed in complex spatial patterns during development. The gene is greater than 100 kb long and has two independently regulated promoters. To characterize cis-acting regulatory elements responsible for the expression pattern, fusions of the Antp promoter 2 cap site and upstream sequences to an Adh-lacZ gene were introduced into flies. A 10-kb sequence directs beta-galactosidase production in a pattern that closely resembles the endogenous P2 pattern. Transcription from the 10-kb fusions is regulated by three genes that regulate Antp transcription. Control elements, including a target of action of homeo-domain-containing proteins, were mapped by deleting parts of the 10-kb sequence.