FIGURE 6:

The TpnC isoform switch is regulated at the transcriptional level. (A–D, A′–D′) Frozen sections of control and experimental flies were stained with phalloidin (green) and with antibody to β-Gal (magenta) and imaged using confocal microscopy. (A, A′) Control line carrying a genomic insertion of TpnC4-lacZ shows reporter expression in the IFMs and not the TDT (TDT is outlined with a dashed line). (B, B′) TpnC41C-knockdown flies carrying the TpnC4-lacZ reporter show lacZ expression expanding into the TDT. (C, C′) Control line carrying genomic insertion of TpnC41C-nLacZ shows reporter expression in the TDT. (D, D′) TpnC4-knockdown flies carrying the TpnC41C-nlacZ reporter show lacZ expression expanding into the IFM (arrows). Note that in C′ and D′, the β-Gal reporter carries a nuclear localization signal and accumulates in muscle nuclei, creating a punctate pattern. Scale bars, 50 µm.