Characterization of the human cytomegalovirus UL34 gene.

UL34 encodes the transcriptional repressor of the human cytomegalovirus immune evasion gene, US3, and is essential for viral replication in tissue culture. Two different monocistronic transcripts originate from UL34 at early and late times postinfection and encode two predominant proteins and a third, minor protein. The UL34 proteins are differentially expressed throughout the viral replication cycle, with both proteins localizing to the nucleus and repressing expression of the US3 gene.