Characterizations of the HCMV UL144 transcripts by 5'-RACE-PCR and 3'-RACE-PCR analyses. 5'-RACE-PCR and 3'-RACE-PCR were performed on first-strand cDNA prepared from total RNA from HELF cells infected with HCMV for 96 h. Strains Xu, Ch, H were analyzed respectively. A 5'-RACE-PCR analysis was performed using the gene specific primers of 144Rev1 and 144Rev2 and the templates prepared with (lanes3, 6 and 9) or without reverse transcriptase (lane1, 4 and 7) during the first strand cDNA synthesis or without tobacco acid pyrophosphorylase (lane2, 5 and 8) during RNA treatment of the isolates. Strains Xu (lanes1-3), Ch (lanes4-6), H (lanes7-9) were analyzed respectively. B 3'-RACE-PCR analysis was performed on first-strand cDNA using the external forward primer 144For2 and the inner forward primer 144For3 by nested PCR together with oligo(dt)17-adaptor. Molecular standards are labeled 'M'. The positions of DL2000 molecular markers are indicated.