The cellular distribution of hA3G in P100 and S100 fractions. H9 cells and 293T cells expressing HA tagged hA3G were lysed in hypotonic TE buffer, and the resultant S1 was ultra-centrifuged, resulting in the P100 and the S100 fractions. The S1, P100 and S100 fractions prepared from 293T cells were analyzed by using a 4-35% discontinuous Opti-prep velocity gradient, as described in Methods. A. Western blots of the S1, P100, and S100 fractions were probed with either anti-hA3G (left) or anti-HA (right) for the samples derived from H9 cells or 293T cells, respectively. B. Nine fractions were collected from the top to the bottom of the gradient, then subjected to Western blot probed with anti-HA. The fraction numbers increase from the top to the bottom of the gradient.