Fig 4.

L4-33K mutant virus particle production. (A) CsCl density equilibrium gradient profiles of virus particles produced from Ad5-WT-, Ad5-Ψ-loxP-, or 33K⁻-infected TetC4 (Cre recombinase-positive), 293, or A549 cells. The arrow and arrowhead indicate empty capsids (EC) and mature virions (MV), respectively. Ad5-Ψ-loxP contains loxP sites flanking the PS and thus produces only EC in TetC4 cells due to cleavage of the PS from the genome by Cre recombinase. (B to F) Electron microscopy examination of the MV and EC isolated in panel A.