Subtractive hybridization cDNA library construction and screening. (A) PDH infected with DHBV, 8 days post-infection. (B) PCR Confirmation of DHBV infection. Upper lane shows the increase in amplification of a DHBV specific gene from days 1 through 8, while the amplification is missing from uninfected controls. (C) Comparison of subtracted and unsubtracted cDNAs on a 2% agarose gel. Individual lanes are marked. Lane 5 is a 100 bp DNA ladder. Lane 8 is a positive control provided with the kit. (D) Analysis of subtraction efficiency using PCR for GAPDH. (E) Macroarray screening by dot-blot hybridization. Each clone is spotted in duplicates. Membranes were hybridized with radio-labelled probes as indicated. The average densitometric intensities of each duplicate clone pair was read for relative abundance calculation.