Figure 1.—

Reptin mRNA expression in wild-type and mutant embryos. Embryos were hybridized with a digoxigenin-labeled antisense reptin RNA probe and are shown with anterior to the left and dorsal up. (A) A precellular wild-type (wt) embryo shows ubiquitous reptin mRNA expression due to its maternal contribution. (B) At stage 13, reptin is expressed in most tissues in a wild-type embryo. (C) In a stage 13 reptin homozygous mutant embryo, no reptin mRNA can be detected. Mutant embryos were identified with the help of a balancer chromosome expressing a Ubx-lacZ reporter gene.