Characterization of the transcripts of human cytomegalovirus UL144

The genome of human cytomegalovirus (HCMV) has been studied extensively, particularly in the UL/b' region. In this study, transcripts of one of the UL/b' genes, UL144, were identified in 3 HCMV isolates obtained from urine samples of congenitally infected infants. Northern blot hybridization, cDNA library screening, and RACE-PCR were used. We identified at least 4 differentially regulated 3'-coterminal transcripts of UL144 in infected cells of 1,300, 1,600, 1,700, and 3,500 nucleotides (nt). The 1600 nt transcript was the major form of UL144 mRNA. The largest transcript initiated from the region within the UL141 open reading frame (ORF) and included UL141, UL142, UL143, UL144, and UL145 ORFs. These findings reveal the complex nature of the transcription of the UL144 gene in clinical isolates.