Contains the osk gene in which the C region cluster of aret response elements (BREs) in the 3' UTR has been mutated.
oskBRE.C- fails to rescue oskA87/Df(3R)osk
83% of embryos derived from oskA87/Df(3R)osk females carrying oskBRE.C- have 0-1 abdominal segments, and 14% have 2-7 abdominal segments.