Cover photograph (Copyright © 2001, American Society for Microbiology. All rights reserved.): Immunofluorescence of human cytomegalovirus (HCMV) immediate-early 2 (IE-2) protein expressed by a rescued clone of an HCMV bacterial artificial chromosome lacking UL122 (T-BAC122R). Human foreskin fibroblasts were transfected with T-BAC122R DNA purified from Escherichia coli. Four days after transfection, the cells were fixed and stained with a monoclonal antibody specific for IE-2 followed by a secondary antibody coupled to Alexa-568 (red). Transfected cells were identified by green fluorescent protein expression (green; mainly localized in the Golgi apparatus) from a cotransfected plasmid. (See related article on page 1870.)