Fig. 2. rdx expression in embryos. rdx mRNA was detected with probe to exons shared by all transcripts (A-I). Probes specific to rdxA or rdxE detected similar expression patterns (not shown). Lateral views show: (A) stage 1-2; (B) stage 4 with pole cells (pc); (C) stage 5; (D) stage 6; (E) stage 8 with anterior midgut (am) and posterior midgut (pm); (F) stage 10; (G-I) stage 11 with stomodeum (sto), ninth abdominal segment (A9), CNS (n) and mesoderm (ms). A ventral view of stage 10 is focused under the ectoderm to show neuroblasts in F. (H) Parasagittal optical section of an embryo homozygous for ci^Ce shows loss of rdx expression in the ectoderm and mesoderm, but retention in the head, in A9 ectoderm, and in the CNS. A similar view of a ptc⁹ homozygous embryo (I) shows extensive ectopic expression of rdx in the ectoderm and mesoderm. The gaps in rdx expression in the ectoderm correspond to posterior compartment cells expressing En (not shown). (J,K) At stage 10/11, En expression (blue) is nestled between stripes of rdx expression (brown), as detected by ß-Gal in rdx¹ embryos. (L) Stage 12 with salivary gland primordium (sg). Dorsal is upwards (except in F) and anterior is towards the left in all panels.