FIG. 7.

Amino acid changes in the N terminus of cdk9HA result in differential localization to the viral transcriptosomes. The cell lines expressing constitutive E55A-, E57A, and R65A-, and Dox-induced E55A/E57A/R65A-cdk9HA virus were infected with HCMV Towne (MOI of 5) and seeded onto glass coverslips. At 8 h p.i., cells were washed with PBS, fixed with 2% FA, permeabilized, and costained with antibodies specific for IE2 and HA (to detect exogenous cdk9HA). Fluorescein isothiocyanate- and tetramethylrhodamine isothiocyanate-conjugated isotype-specific secondary antibodies were used. Nuclei were stained with Hoechst dye. The white arrows marked “n” indicate viral transcriptosomes with no colocalization between stained proteins, and the unmarked white arrows show examples of colocalization. All of the images represent confocal optical 0.2-μm sections at a magnification of ×1,000 under conditions of oil immersion.