Imprecise excision of the progenitor insertion, resulting in a 1615bp deletion that removes 697bp upstream of the stck ATG codon and 918bp downstream of it (this removes the region encoding amino acid residues 1-228).
parvin694 ; Ilk54stckT2 triple mutant embryos have actin clumps that are detached from the muscle attachment sites, as occurs in single mutant embryos.