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Figure 1 | Retrovirology

Figure 1

From: Mutations affecting cleavage at the p10-capsid protease cleavage site block Rous sarcoma virus replication

Figure 1

A. Schematic diagram of the RSV Gag polyprotein and the amino acid substitutions placed in the p10-CA protease cleavage site within Gag. The rectangle represents the RSV Gag polyprotein with the encoded protein sequences indicated by the standard nomenclature. The horizontal lines represent the PR cleavage sites. SP is the spacer peptide. The L domain of RSV Gag resides in the p2b peptide. In the box below, the P4-P1 and P1'-P4' amino acid sequence of the wild type p10-CA protease cleavage site is shown. The p10-CA mutants (underlined bold text) are shown below the wild type sequence. The results of in vitro protease assays examining RSV PR-mediated cleavage of peptides containing the wild type (PVVAM*PVVIKRR) and mutant p10-CA sites are also indicated. The site of p10-CA cleavage is designated with an asterisk. B. Top, Effect of p10-CA amino acid substitutions on processing of RSV Gag. COS-1 cells were transfected with wild type Gag or the p10-CA mutants in pSV.Myr0(HpaI). 48 hours after transfection, cells were labeled with [35S]-Met and Cys and Gag proteins were immunoprecipitated with an anti-RSV rabbit antiserum from the media (right panel) and lysate (left panel) fractions. Immunoprecipitated proteins were separated by SDS-PAGE and exposed to film. Lane 1, untransfected cells. Cells transfected with wild type, lane 2; M239F, lane 3; M239G, lane 4; P240F, lane 5; V241G, lane 6. B. Bottom. Effect of p10-CA amino acid substitutions on Gag release in the context of a protease inactivating substitution (PR-D37S). COS-1 cells were transfected and full-length Gag proteins were immunoprecipitated and separated by SDS-PAGE as above. Cells transfected with M239F/PR-D37S, lane 1; M239G/PR-D37S, lane 2; P240F/PR-D37S, lane 3; V241G/PR-D37S, lane 4; untransfected cells, lane 5; PR-D37S, lane 6.

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