Escherichia coli lacZ, which encodes beta-galactosidase, has become a
widely used reporter gene to study the developmental regulation of gen
e expression in a variety of organisms. To detect the presence of the
beta-galactosidase, the sample must be fixed and appropriately stained
. This sort of analysis yields rather crude estimates of the spatial t
emporal changes in gene expression patterns. In addition, one cannot r
ecover interesting specimens for propagation. A novel fluorogenic beta
-galactosidase substrate for use in live Drosophila melanogaster embry
os has been designed and synthesized This compound provides a means to
determine gene dosage in live embryos so that one cart unambiguously
determine the genotype of a living embryo. This will be useful for det
ailed analysis of cellular and morphogenetic behavior changes in live
embryos that are homozygous for embryonic lethal mutations. in the cou
rse of testing this compound, a new beta-galactoside hydrolytic activi
ty, different from the previous ly identified beta-galactosidase, has
been discovered to reside in macrophages and the intervitelline space.