An Hsp83 promoter drives expression of a mutated form of the lncRNA:roX1 c20 cDNA, with a mutation in part of the stem loop structure.
roX1ex6 Df(1)52/Y males carrying P{w+4Δ4.3} generally do not survive to adulthood. This lethality is partly rescued by an autosomal copy of roX15'S.Hsp83.