Figure 5.

Reduced and ectopic expression of sim in Su(H) mutant embryos. In situ hybridization of Su(H)^del47 P[l(2)35Bg⁺] mutant embryos showing the distribution of sim transcripts at stages 5 (A,A′) and 8 (B,B′). (A,A′) Low levels of sim expression were detected in two to three cell rows at stage 5 (lateral view; A′ is an enlarged view of the same embryo). Accumulation of sim transcripts at the posterior pole is out of focus. (B,B′) Occasionally, a few cells located at the midline failed to express sim, creating small gaps. In other regions, cells expressing high levels of sim transcripts were observed in one to two rows of cells away from the midline at stage 8, forming small clusters (ventral views). No discernable pattern of gaps and clusters was recognized.