Sequence analysis of the nuclear Drosophila serendipity delta Cys-2/His-2 finger protein indicated the presence of a short motif of positively charged amino acids, with homology to the SV40 large T and c-myc nuclear localisation signals. Using P-element mediated transformation we constructed transgenic Drosophila lines expressing beta-galactosidase fusion proteins, containing (or not) an 18 residue segment of sry delta including this basic, PTKKRVK, motif. Histochemical detection of fusion proteins on dissected tissues showed that this segment of sry delta can act autonomously to drive the beta-galactosidase in nuclei.