Wild-type His2A gene in the context of a histone gene repeat unit.
The sensory bristles in Df(2L)HisC 4xM{3xHisGU.wt} mutant flies appear indistinguishable from controls.
Df(2L)HisC, His1HisGU.wt, His2AHisGU.wt, His2BHisGU.wt, His3HisGU.wt, His4HisGU.H4K16R, His4rΔ has short lived | female limited phenotype
Df(2L)HisC, His1HisGU.wt, His2AHisGU.wt, His2BHisGU.wt, His3HisGU.wt, His4HisGU.wt, His4rΔ has fertile phenotype
Df(2L)HisC, His1HisGU.wt, His2AHisGU.wt, His2BHisGU.wt, His3HisGU.wt, His4HisGU.H4K16Q, His4rΔ has short lived phenotype
Df(2L)HisC, His4rΔ double homozygotes rescued by 12x copies of the HisGU gene unit (bearing His1HisGU.wt, His2AHisGU.wt, His2BHisGU.wt, His3HisGU.wt and His4HisGU.wt) are semi-lethal and adults are fertile and show normal lifespan.
Epidermal Df(2L)HisC clones in His4rΔ homozygotes that also express variants of the HisGU gene unit (12 copies; bearing His1HisGU.wt, His2AHisGU.wt, His2BHisGU.wt and His3HisGU.wt with either His4HisGU.wt, His4HisGU.H4K16R, His4HisGU.H4K16Q or His4HisGU.H4K16A) are able to form normal-looking adult structures with sensory bristles.
His2AHisGU.wt rescues Df(2L)HisC
Clones containing Df(2L)HisC mutant cells stop proliferating, but are rescued in animals that also carry four copies of M{3xHisGU.wt}.
Increasing copy numbers of the histone gene repeat unit provided by transgenic constructs can rescue the Df(2L)HisC phenotype: Df(2L)HisC homozygotes that are also homozygous for M{1xHisGU.wt} develop a defective cuticle. Df(2L)HisC homozygotes that are also homozygous for M{3xHisGU.wt} develop a wild-type cuticle pattern but fail to hatch. Df(2L)HisC homozygotes that carry four copies of M{3xHisGU.wt} (homozygous for two different insertions of M{3xHisGU.wt}) are rescued to become fertile adults with no visible morphological defects.