Figure 2

Lms and Ap positively regulate the expression of dCryAB and Gel in LT muscles. dCryAB and Gel transcript expression were analysed in heterozygous lms + /-;ap + /- (A–B′) embryos, in single lms-/- mutant embryos (C–D′) and in double lms-/-;ap-/- mutants (E–F′) by in situ hybridisations with dCryAB or Gel RNA probes. (A–B′) Both dCryAB and Gel are prominently expressed in LT muscles of heterozygous lms + /-;ap + /- embryos. By contrast, dCryAB transcript levels are reduced in LTs (underlined area) in simple lms-/- mutants (C–C′) compared to (A, A′). Note that in lms mutants, dCryAB expression in DT1 remains unaffected (arrow). dCryAB down-regulation in a few remaining LTs is even more apparent (arrowheads) in double lms-/-;ap-/- mutants in which dCryAB expression in SBM and in DT1 is still detectable (arrows). Gel LT expression in the lms-/- context has almost completely vanished (underlined area) in (D) compared with (B), whereas its expression in the fat body (FB) remains high. No LT associated Gel expression could be detected in double lms-/-; ap-/- mutants. Note that Gel expression in FB could still be detected (F). Conversely, pan-muscular expression of ap using Mef2-Gal4 driver induces both dCryAB (compare G, G′, with I, I′) and Gel expression (H, H′, J, J′) in all muscles. Arrowheads point to LT muscles and arrows point to ectopic expression in dorsal (I) and ventral (J) muscles). (K) Schematic representation of dCryAB and Gel transcriptional regulation.