04-病毒学virus巴斯德研究所.pptVIP

Figure 5-6 Replication scheme of double-strand RNA viruses. After entry and partial uncoating (step 1), dsRNA segments within subviral cores are transcribed by the core-associated RNA-dependent RNA polymerases (RdRps) to produce mRNAs (step 2) for the viral proteins (step 3). These form subviral particles around the mRNAs (step 4), which are then copied to produce genomic dsRNAs (step 5). Progeny subviral particles contribute to viral gene expression (steps 6 and 7) and replication (steps 8 and 9), and assemble with outer shell structural proteins to form progeny virus particles (step 10). For further details, see Chapters 52, 54, and 56. Figure 5-7 Replication scheme of retroviruses. After entry and partial uncoating (step 1), genomic RNA is copied to dsDNA by reverse transcriptase (steps 2 and 3) and covalently integrated into cellular DNA in the nucleus by DNA integrase (step 4). Both enzymes are present in the viral core. The integrated viral genome (or provirus) is transcribed by cellular RNA polymerase II (step 5) to produce viral RNA transcripts that function both as precursors to mRNAs for the viral proteins (steps 6 and 7) and for assembly into progeny virus particles (step 8). For further details, see Chapter 58. Figure 86-3 Schematic depiction of the hepadnaviral life cycle. See text for details. Figure 57-3 Generalized retrovirion structure and components. A highly schematic view of the arrangement of viral gene products within the virion particle. The two-letter nomenclature for each protein is indicated. Figure 57-4 The organization of the retroviral RNA genome. The single-stranded RNA genome is depicted as a curved line. From 5′ to 3′ along the RNA, the features include a 5′ cap structure; R, a sequence block repeated at both 5′ and 3′ ends; U5, a unique 5′ sequence block; pbs, the primer binding site and site of initiation of minus-strand DNA synthesis; Y, the major recognition site for the packaging of the viral RNA into the virion particle; the gag