Expression of mir-1^Scer\UAS.cKa under the control of Scer\GAL4^tin.CΔ4 results in a significant increase in cardiac arrhythmia, although average lengths of diastolic and systolic intervals are not significantly change, as compared to controls.

Ubiquitous expression of mir-1^Scer\UAS.cKa under the regulation of Scer\GAL4^da.G32 or Scer\GAL4^how-24B results in 100% embryonic lethality at various stages of development. Approximately 21% of overexpressing flies exhibit disrupted patterns of cardiac and skeletal muscle with insufficient numbers of cardioblasts, which are often enlarged compared to wild-type (3-4 cardioblasts per hemisegment compared to six cardioblasts per hemisegment in wild-type). Expression of mir-1^Scer\UAS.cKa using Scer\GAL4^dpp.blk1 results in thickening of the wing veins, particularly in longitudinal veins 3 and 4 (L3 and L4), along with a shortened-leg phenotype.