FIG. 4.

Expression of PCNA lacZ during development. Male transgenic flies were crossed with female wild-type flies and extracts were prepared from Drosophila bodies at various stages of development. The β-galactosidase activities in the extracts are expressed as absorbance units per h per mg protein. Black bars indicate the averaged value of eight independent transgenic strains carrying p5′-607DPCNAlacZW8HS. Hatched bars indicate the averaged value of six independent strains carrying the p5′-168DPCNAlacZW8HS. Deviation between independent strains is also indicated.