6.4kb XbaI-BamHI fragment spanning the su(f) locus (missing the last 66 amino acids from the C terminus), the last exon is fused in frame to sequence encoding the lacZ reporter.
wild-type
su(f)G.lacZ rescues su(f)4
su(f)G.lacZ fails to rescue su(f)8
su(f)G.lacZ fails to rescue su(f)19