HCMV IE and L gene expression in the macrophages derived from infected CD34⁺ BM progenitor cells 28 days postinfection. (A) Ethidium bromide-stained 1% agarose gel of RT-PCR products of IE transcripts. The arrows indicate the RT-PCR products of unspliced IE transcripts of 332 bp and spliced IE transcript of 218 bp. Lane 1, RNA from the cultures infected with 95(2); lane 2, RNA from the cultures infected with Towne/lox²; lane 3, RNA from mock-infected cultures; lane 4, positive control of HCMV-infected fibroblasts displaying both the genomic size (unspliced; 332 bp) banding pattern and the RNA size (spliced; 218 bp) banding pattern; lane 5, RT-PCR H₂O control. (B) Ethidium bromide stained 1% agarose gel of RT-PCR products of MCP transcripts. The arrows indicate RT-PCR product of unspliced MCP gene of 638 bp. Lane 1, RNA from the cultures infected with 95(2); lane 2, RNA from the cultures infected with Towne/lox²; lane 3, RNA from mock-infected cultures; lane m, 100-bp ladder (GIBCO/BRL). All RNA samples were treated with Rnase-free Dnase. Primers and predicted PCR products are listed in Table 1.