Fat-body-specific expression of the Drosophila Lsp-2 gene.

The larval serum protein-2 gene (Lsp-2) of Drosophila melanogaster is expressed at a very high level in the fat body of third-instar larvae. Here we report that Lsp-2 transcription in adult flies produces a unique mRNA localized in the adult adipose tissue of the head in both sexes. To identify regulatory regions of this Drosophila gene, Lsp-2 5'-flanking DNA sequences were fused to the E. coli beta-galactosidase gene (lacZ). Transient expression of the hybrid gene in third-instar larvae indicates that 230 bp just upstream from the 'TATA box' of the Lsp-2 gene are sufficient for larval fat body-specific expression.