FIG. 2.

Southern analysis of the HBV DNA present in cis and trans cores. (A) HBV DNA extracted from equal amounts of purified cis (ECPE and CPE) or trans (C+PE) cores was resolved on alkaline agarose gels. After alkaline capillary transfer to a nylon membrane, minus-strand DNA [(−) DNA] was disclosed by hybridization with a radiolabeled plus-strand riboprobe. Lane M, labeled HindIII λ DNA markers (in kilobase pairs); lane HBV, 1.9- and 0.6-kb HBV DNA markers. (B) DNA extracted from purified ECPE, CPE, and C+PE cores was resolved on alkaline agarose gels and then membrane immobilized. Note that a threefold excess of cis cores was used for this experiment. HBV DNA species of minus (left) and plus (right) polarities were detected by hybridization with riboprobes of the opposite polarities. Migration of radiolabeled λ HindIII markers (lanes M) and HBV-specific 3.2-, 2.6-, 1.9-, and 0.6-kb DNA fragments (lanes HBV) is indicated on the left. (C) Analysis of phenol-extractable HBV minus-strand DNA was performed essentially as described for panel B, with a plus-strand riboprobe. Aliquots of HBV DNA extracted from CPE-derived cis cores and C+PE-derived trans cores were phenol extracted with (+) or without (−) prior digestion with proteinase K. The latter samples were boiled in the presence of SDS and DTT to disrupt the capsids prior to extraction.