Altered patterns of segmentation gene expression in dCtBP mutants

Embryos were obtained from dCtBP germline mosaics and hybridized with digoxigenin-labeled antisense RNA probes. The staining patterns were visualized by histochemical staining, and the embryos are oriented with anterior to the left and dorsal up (except K and L). (A and B) Kruppel expression pattern in wild-type (A) and dCtBP mutant (B) pre-cellular embryos. Strong staining is observed in central regions, and a weak pattern is detected in head regions. As shown previously (Poortinga et al., 1998), the Kruppel expression pattern is essentially normal in mutant embryos. (C and D) knirps expression pattern in wild-type (C) and dCtBP mutant (D) pre-cellular embryos. Staining is detected in both a band in the presumptive abdomen and an extended patch in antero-ventral regions. The knirps pattern is essentially normal in the mutant embryos (Poortinga et al., 1998). (E and F) giant expression pattern in wild-type (E) and dCtBP mutant (F) pre-cellular embryos. giant is expressed in both anterior and posterior regions. The posterior band is expanded in mutant embryos (see brackets). A similar alteration in giant expression is observed in Kruppel mutants (Kraut and Levine, 1991). (G and H) eve expression pattern in wild-type (G) and dCtBP mutant (H) cellularized embryos. There is a severe disruption in the eve pattern, with a loss of stripes 4–6 and a fusion of stripes 2 and 3. This altered pattern combines features seen in knirps- and Kruppel- mutants (see I and J). (I) eve expression pattern in knirps- embryo. There is a loss of stripes 4, 5 and 6. (J) eve expression pattern in Kruppel- embryo. Stripes 2 13 and 4–6 are fused into two broad bands. (K) eve stripe 2 expression in a wild-type, gastrulating embryo. A lacZ reporter gene driven by the minimal, 480 bp stripe 2 enhancer was visualized with a lacZ antisense RNA probe. (L) Same as (K) except that the stripe 2 reporter gene was crossed into a mutant embryo derived from a dCtBP germline clone. There is a pos