Fig. 6. Evidence for bona fide activation by En. (A,B) Expression of hh (A) and en (B) in the abdominal region of slp (34B) mutant embryos. The expression patterns are identical. Note that expression widens in even-numbered segments, whereas it is decaying in oddnumbered segment (see Cadigan, 1994). (C,D) Expression of hh in slp (34B) mutant embryos that express either En (C) or VP16En (D) in the paired domain. Expression of hh is in purple and that of VP16En is in ochre. In both cases, hh expression is activated, especially in the ventral region (compare with homologous segments in plain slp^-, panel B). Thus, in the absence of the repressor Slp, VP16En and En have the same effect on expression of hh (and also of en; not shown). By contrast, in the presence of slp, expression of hh is activated by En (Fig. 1D), whereas it is repressed by UAS-VP16En (Fig. 4B). Note that, in slp^-1, the effect of VP16En is stronger than that of En.

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