A Drosophila GATA family member that binds to Adh regulatory sequences is expressed in the developing fat body

We have identified a Drosophila transcription factor that binds a sequence element found in the larval promoters of all known alcohol dehydrogenase (Adh) genes. DNA sequence analysis of cDNA clones encoding this protein, box A-binding factor (ABF), reveals that it is a member of the GATA family of transcriptional regulatory factors. ABF-binding sites within the D. mulleri and D. melanogaster larval Adh promoters function as positive regulatory elements and in cotransfection experiments, ABF functions as a transcriptional activator. In further support of a role for ABF in the regulation of Adh expression, ABF mRNA is expressed in the embryonic fat body, a tissue that contains high levels of Adh mRNA. Our studies demonstrate that the fat body develops from segmentally repeated clusters of mesodermal cells, which later expand and coalesce to form the mature fat body. These observations establish ABF as the earliest known fat body precursor marker in the Drosophila embryo. Together with the established role of GATA factors during mammalian development, these results suggest that ABF may play a key role in the organogenesis of the fat body.