Figure 1

Transient RNAi Pulse Induction causes chronic gene knockdown in adult fly adipose tissue. (A) Overview of double-strand (ds) or short-hairpin (sh) RNAi Pulse Induction (RiPI) regimen for chronic gene impairment in adult flies. (B) Detailed scheme showing the time period (from 18 °C to 29 °C for 38–48hs, starting at day 6 after eclosion of adult flies) of Temperature-sensitive RiPI (TRiPI, based on TARGET system) on target genes, i.e. AkhR. TRiPI On refers to TRiPI activity in response to pulse induction at 29 °C was switched on in adult flies (red bar). TRiPI Off refers to TRiPI activity was at off state in adult flies as they were kept at 18 °C (light red bar). TRiPI On control refers to flies containing the RNAi transgene only, which were also transiently shifted to 29 °C (deep green bar); TRiPI Off control refers to flies of the same genotype compared to TRiPI On control flies, kept constantly at 18 °C (light green). (C) Abdominal GFP mRNA expression of TRiPI flies containing temperature-sensitive GFP transgene displayed substantial higher expression level at day 1 compared to day 10 after Stim-TRiPI On as compared to Stim-TRiPI Off males. (D) High abundance of AkhR RNAi effector (siRNA) produced from the AkhR-shRNAi transgene at day 0 and maintained at significant high levels at day 10 in the abdomen of AkhR-TRiPI On males when compared to AkhR-TRiPI Off males. Relative (Rel.) mRNA or siRNA levels are represented as fold change, which refers to the basis value (=1) obtained from corresponding TRiPI Off. (E) Fly abdominal AkhR mRNA expression level reduced at day 1  and day 10 after AkhR- TRiPI On as compared to AkhR-TRiPI Off males. Relative (Rel.) GFP, siRNA or AkhR RNA levels are represented as fold change, which refers to the basis value (=1) obtained from corresponding TRiPI Off flies. Data are presented as means ± standard deviations from 3–6 replicates. All data were analyzed by the two-tailed unpaired Student’s t-test. No *p ≥ 0.05, *p < 0.05, **p < 0.01, ***p < 0.001.