Reporter gene expression is restricted to five lateral chordotonal organs in abdominal and thoracic segments. In embryos mutant for N, Dl, bib, neu, amx, and E(spl), the specificity of expression is maintained but the number of SMCs/cluster increases.

In late embryo, expression in all lateral and dorsal chordotonal organs of the body segments: highest level in scolopidial sheath cell, also consistently observed in scolopidial cap cell; expression in a few other cells, including some support cells of other external sensory organs and pericardial cells.