Figure 4 |. Inhibition of reverse transcriptase rescues type I interferon response in SIRT6 KO mice.

A, B, SIRT6 KO mice display a robust type I interferon-α (A) and β (B) response that is rescued by NRTI treatment. Organs were harvested from 27 days old mice and interferon mRNA was quantified by qRT-PCR. Data normalized to actin and WT heart was used as a reference. Impact NRTI treatment on the WT control mice is shown in Figure S2A, B. n=5 animals per group, error bars show s.d. Black asterisks indicate significant differences from WT, and red asterisks indicate significant differences from water-treated SIRT6 KO.

C, D, SIRT6 KO MEF lines were generated with stably integrated siRNA or shRNA cassettes targeting conserved sequences at the 5’ portion of L1 MdA family. Both cassettes rescued IFN-α/β expression.

E-G, NRTI anti-RT activity is essential for L1 suppression and rescue of type I interferon response. Cells were treated with 10 μM/ml of unmodified NRTI or methylated d4T (mD4T) for 30 PD. See Figure S2D for additional analysis of methylated D4T. L1 DNA content (E) and IFN-α/β expression (F, G) were assayed by qPCR and qRT-PCR. The data was normalized to actin and WT values were used as a reference.

Statistical significance was determined by the Student’s t-test and asterisks indicate p < 0.05.