Incoming HIV-1 persistently reside at the centrosome of resting cells. A. Cycling but not resting MRC5 cells support viral gene expression. To obtain a resting cell population, MRC5 were grown to confluence, growth-arrested by serum starvation and cultured in the presence of 10-6 M dexamethasone. MRC5 cells were transduced with a VSVg-pseudotyped lentiviral vector carrying the GFP reporter gene and GFP-expression was measured by flow cytometry at 48, 72 and 96 h post-transduction. B. Incoming HIV-1 CA localizes at the centrosome in transduced MRC5 cells. Cells were immunostained and analyzed by confocal microscopy as described above. C. HIV-1 CA but not MA protein can be detected in the total cell extracts of transduced resting MRC5 up to 28 days post-transduction. Total cell extracts were obtained by boiling both transduced and control cells, pre-treated with pronase (10 min, 4°C), in SDS-PAGE sample buffer. Proteins were resolved by SDS-PAGE and detected by Western blotting with mouse anti-MA or mouse anti-CA ab.