FIGURE 5.

Knockdown of Dstac in body-wall muscles reduced Dmca1D expression level and muscle Ca²⁺ transients. (A) Anti-Dmca1D labeling of Dstac^ΔSH3 larval muscles (n = 36 stripes from 12 muscles) showed decreased level of Dmca1D at T tubules compared with wt (n = 42 stripes from 14 muscles). One-tailed Mann Whitney test. Right images are a single focal plane of muscle 4 of a wt and a Dstac^ΔSH3 larvae. Arrows denote striations of Dmca1D clusters. Scale bar, 3 μm. (B) Same as in (A) except the peak fluorescence of stripes was measured. Fluorescence of individual pixels along a longitudinal line that crossed multiple stripes of muscle fibers was measured from Dstac^ΔSH3 (n = 40 stripes from 13 muscles) and wt (n = 52 stripes from 14 muscles). One-tailed Mann Whitney test. Right images are examples of fluorescence measurements along the longitudinal line of wt and Dstac^ΔSH3 muscles. (C) Example of Ca²⁺ transients from a muscle in a control larva (Mef2:GAL4 > UAS:GCaMP6f; UAS:mCD8tdTomato; UAS:Luciferase^RNAi) and a Dstac^RNAi larva (Mef2:GAL4 > UAS:GCaMP6f; UAS:mCD8tdTomato; UAS:Dstac^RNAi). (D) The level of GCaMP6f fluorescence in muscles of Dstac^RNAi larvae was higher than that of control. Unpaired t test. (E) The peaks of Ca²⁺ transients in the muscles of Dstac^RNAi larvae were smaller compared with controls. One-tailed Mann-Whitney test. (F) The number of Ca²⁺ transients over 5 min in Dstac^RNAi and control muscles were comparable. Mann-Whitney test. Data in D-F were from 15 muscles of 5 control larvae and from 15 muscles of 5 Dstac^RNAi larvae. *P < 0.05, ***P < 0.001, and ****P < 0.0001.