Fig 2: HBV RNA sequences are imported into mitochondria.a Alignment of nucleotide sequences and secondary structures of mitochondrial RNA targeting signals in RNase P and HBV PreS1 RNAs (GenBank reference sequence: NC_003977; HBV genome nucleotides: 3049–3065). b PNPASE immunoblot from HepG2 and HepAD38 cells. β-Tubulin was used as a loading control. c In vitro import of HBV RNA fragments corresponding to PreS1 (including the putative PreS1 targeting signal), Polymerase (Pol) (including Stem-loop α, SLα), pgRNA (including epsilon) and X (including Stem-loop β, SLβ) transcripts as well as of a COX3 mRNA fragment into mitochondria from HepG2 cells. In vitro-transcribed PreS1, Pol-SLα, epsilon and X–SLβ, or COX3 RNA (Input) were incubated with mitochondria from HepG2 cells. Not-imported RNA was digested with nuclease. d Quantification of the relative import level by densitometry measurements.