A3B slows down adenovirus propagation by a deaminase-dependent mechanism.

Immortalized human bronchial epithelial cells HBEC3-KT were transduced to stably express the GFP, the APOBEC3B protein (A3B) or a catalytically inactive version of the APOBEC3B protein (A3B-DD for Deaminase Dead). (A) A3B mRNA levels were quantified by RTqPCR and expressed relative to GAPDH mRNA level. (B) A3B protein levels were assessed by western blot, quantified by densitometry and normalized with HSP90. (C) Total proteins were extracted in a non-denaturing buffer and mixed with the substrate of the deamination assay. Deaminase activity, if present in the cell lysate, will allow the conversion of substrates into shorter products. Substrates and products were quantified by densitometry. Deamination activities of the cell lysates were expressed as the percentage of substrate converted into product. P-values were calculated by t-tests. (D-E) HBEC-WT, -GFP, -A3B and -A3B-DD were infected with HAdV-A12, -B3 or -C2 at a MOI = 0.03. The percentage of infected cells were quantified by flow cytometry at different time points post infection. The results of the 3 biological replicates are shown separately (D) or pooled together (E). P-values were calculated by ratio t-tests. Only significant differences are shown.