UAS regulatory sequences drive expression of a full-length Hnf4 open reading frame (ORF) that is tagged at the C-terminal end with three copies of the Tag:HA epitope. The ORF is flanked by a pair of incompatible FRT sites (FRT5 and FRT2), which allows for future in vivo exchange of either the promoter or tag sequence.
Third instar larval garland nephrocytes expressing Hnf4UAS.ORF.GW.Tag:HA under the control of Scer\GAL4Ugt36A1.PK exhibit a severe decrease in lipid droplet content (BODIPY staining) when expressing at low levels (18[o]C), or exhibit a strong lipid droplet accumulation when expressing at higher levels (29[o]C). Unlike controls, there is abundant cytoplasmic phagophores and autophagosomes, whose limiting membranes are often multilamellar in structure; unlike the perinuclear compact ER decorated with ribosomes observed in controls, ER structures are difficult to detect despite their abnormal expansion.
High expression of Hnf4UAS.ORF.GW.Tag:HA under the control of either Scer\GAL4Ugt36A1.PK or Scer\GAL4sns.GCN causes a reduction in the size and number of third instar larval nephrocytes, as compared to controls.
Expression of Hnf4Scer\UAS.ORF.GW.T:Ivir\HA1 under the control of Scer\GAL4Bx-MS1096 results in partial female lethality at 18[o]C. The adult flies that are seen exhibit almost complete wing loss at 18[o]C.
Hnf4UAS.ORF.GW.Tag:HA, Scer\GAL4Desat1.PB is a suppressor | partially of abnormal courtship behavior phenotype of Scer\GAL4Desat1.PB, fruKK112763
Hnf4UAS.ORF.GW.Tag:HA, Scer\GAL4Desat1.PB is a suppressor | partially of lipid droplet | increased number | adult stage phenotype of Scer\GAL4Desat1.PB, fruKK112763
Hnf4UAS.ORF.GW.Tag:HA, Scer\GAL4Ugt36A1.PK is a non-suppressor of lipid droplet | third instar larval stage phenotype of Scer\GAL4Ugt36A1.PK, mdyHMC06242
Hnf4UAS.ORF.GW.Tag:HA, Scer\GAL4Ugt36A1.PK is a non-suppressor of embryonic/larval garland cell | third instar larval stage phenotype of Scer\GAL4Ugt36A1.PK, mdyHMC06242
Co-expressing mdyHMC06242 and Hnf4UAS.ORF.GW.Tag:HA under the control of Scer\GAL4Ugt36A1.PK abolishes lipid droplets in third instar larval garland nephrocytes in both high (29[o]C) and low (18[o]C) Hnf4UAS.ORF.GW.Tag:HA expressing conditions.