In Drosophila, proteins containing leucine-rich repeats (LRR) play diverse roles during embryonic development. In particular, they function in cell adhesion and cellular signalling and have in common the ability to mediate reversible protein-protein interactions. The sequence and chromosomal location of Drosophila LRR47, which encodes a protein with eight LRR repeats, were reported previously. In this paper the 5' flanking region of the LRR47 gene is described and the initiation point for the maternal transcription unit is defined. LRR47 belongs to a subfamily of LRR proteins that have in common the ability to interact with ras GTPase. Whole-mount in situ hybridization studies show that the LRR47 transcript is uniformly distributed in early cleavage embryos but becomes depleted at the termini by the blastoderm stage. There is a specific requirement for ras function in the embryonic termini at this developmental stage. The distribution of LRR47 protein in embryos and tissue culture cells was also studied. The protein is present in both the cytoplasm and nuclei of embryos until gastrulation and is seen to persist in the nuclei of the amnioserosa until later stages of development. The protein is also constitutively present in growing SL2 culture cells and again is present in both cytoplasm and nuclei. These results suggest that LRR47 function may be modulated in the cell or nuclear division cycle.