PT - JOURNAL ARTICLE AU - Macias, A. AU - Casanova, J. AU - Morata, G. TI - Expression and regulation of the abd-A gene of Drosophila DP - 1990 Dec 01 TA - Development PG - 1197--1207 VI - 110 IP - 4 4099 - http://dev.biologists.org/content/110/4/1197.short 4100 - http://dev.biologists.org/content/110/4/1197.full SO - Development1990 Dec 01; 110 AB - We have developed a specific polyclonal antibody that recognizes the protein products of the abdominal-A (abd-A) gene, a member of the bithorax complex of Drosophila. The normal expression domain extends from parasegments 7 to 13, in good correspondence with previous genetic and molecular results. However, while the anterior border of expression is precisely demarcated by a parasegmental boundary, the posterior border does not coincide with a lineage boundary. Within the normal domain, the expression of abd-A shows intrametameric modulation; the amount of product is higher in posterior compartments and in the most anterior cells of the anterior compartments and then gradually decreases. We have examined the effect on abd-A expression of a number of mutations, some mapping within and others outside the abd-A transcription unit. Those mapping to the transcription unit eliminate or severely reduce the amount of abd-A antigen, while those mapping outside produce an abnormal distribution of abd-A protein. Finally, we show that the abd-A gene is down-regulated in part of the Abdominal-B (Abd-B) domain, precisely in those regions where the Abd-B gene is expressed at high levels.