The pUL21a-RXL/Cy motif is required for Cyclin A2 repression by HCMV.

<p>Density arrested human embryonic lung (HEL) fibroblasts were infected with HCMV reconstituted from TB40-BAC4-wt or derivatives carrying the indicated UL21a mutations. Cells were harvested at regular intervals and analyzed for viral and cellular gene expression by immunoblotting (A) and ribonuclease protection assay (B). Cell culture supernatants were analyzed for the number of IE protein-forming units (IU) by virus titration (C). Results are represented as mean values plus standard deviations of triplicate samples.