Carries the 5' end of msl-2SXB1-2 and the 3' end of msl-2MM2SV such that it lacks all poly(U) clusters, consensus Sxl binding sites.
wild-type
Df(1)52, P{w+4Δ4.3}, msl-2NOPU has lethal | female phenotype
msl-2NOPU rescues msl-21