Fig. 2. dimm is required for expression of normal levels of peptide transmitters. (A) The 39C4-D1 region of chromosome 2L showing the locations of the c929 and KG02598 (`2598') P element insertions (triangles), the CG18362, cryptocephal (crc) and dimm (CG8667, Mistr) genes, and local deletions (wavy lines; bars indicate breakpoint uncertainties). TW1 (not shown) deletes 38A7-B1 to 39C3, ending 17 kb distal to the c929 insertion (Hewes et al., 2000). Rev18 deletes chromosomal bands 39A3-7 to 39D3-5 (A. Carpenter, personal communication). Rev4 deletes 39C1-4 (Hewes et al., 2000) and is a molecular null for the dimm gene (D. Eberl, personal communication; data not shown). Introns smaller than 70 bp are not shown. A segment of DNA extending toward the telomere (wild type) was deleted without affecting neuropeptide levels in the CNS. A second region (dimm 5') was required for the maintenance of normal neuropeptide levels and probably contains dimm 5' enhancer elements. (B) The dimm mutant phenotype for a peptide biosynthetic enzyme, PHM. Reduction in PHM immunostaining in the CNS of a third instar dimm^-/- larva (B'), compared with a dimm^+/- sibling control (B) (n=28). (C) The dimm mutant phenotype for neuropeptides related to MM. Reduction in MM immunostaining in the CNS of a first instar dimm^-/- larva (C'), compared with a dimm^+/- sibling control (C) (n>50). (D) Phenocopy of the dimm^-/- phenotype (MM immunostaining) by injection of double-stranded CG8667 RNA into wild-type embryos (D'), compared with a mock (saline-injected) control (D) (n=7). Asterisk, weak signal in midline S2 and/or S1a neurons. (E,E') The dimm mutant phenotype in the endocrine Inka cells. Anti-MM immunostaining of an Inka cell in a third instar dimm^-/+ larva Inka cell immunostaining [E; compare with O'Brien and Taghert (O'Brien and Taghert, 1998)] was no longer detectable in a dimm^-/- larva (E'). The apparent increase in background in E' is due to the incidence of air pockets in the tracheae of this specimen. The precise location of the Inka cell is variable and not certain in (E'); however, it is normally within this image field. Scale bars: 50 µm.

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