Fig. 3. The GAL4/UAS transplantation system highlights syncytia in third-instar larvae. (A) The expression of GFP, here used as a cell-lineage marker, demonstrates that the descendants of a single transplanted cell gave rise to two cells of the fat body (insert) and also contributed to a larval somatic muscle. (B) Only the muscle fraction of the clone expresses the syncytia marker ß-galactosidase as revealed by X-Gal staining.