Fig. 3. DRI is not involved in initiation of the glial cell fate or repression of the neural cell fate decision in lateral glioblasts. (A) dri expression in longitudinal glia of a stage 12 embryo (arrow). (B) Whole-mount stage 12 dri¹/dri² embryo, derived from a maternal dri¹ homozygous germline clone, stained with anti-REPO antibody. Loss of maternal and zygotic DRI does not interfere with the early behaviour of the LG. (C) Wild-type stage 15 embryo stained with anti-REPO antibody. (D) Ectopic expression of dri in the mesectoderm using sim-GAL4 does not induce longitudinal glial cell fate specification, as detected by anti-REPO staining (compare with C). (E) Ectopic expression of dri in parasegments T2-A4 using Kr-GAL4 (between arrowheads) does not inhibit neural differentiation, as detected by anti-ELAV antibody. (F) 22C10 antigen is correctly localized in a single somatic muscle fibre in dri¹/dri² homozygotes (arrowheads).