GMR regulatory sequences drive expression of a mir-6-1 microRNA in which 22bp of sequences complementary to ec have been substituted into the precursor stem backbone at the position normally occupied by the mature mir-6-1 miRNA. This results in an artificial miRNA that targets 21bp within the ec gene. The targeted sequence is surrounding the catalytic cysteine of the ec-SF1 isoform (residues 562-583).
Flies expressing ecmiRNA.SF1.GMR have a rough eye phenotype and extra interommatidial cells are present in the pupal retina.