Schematic diagram of recombinant HCMVs containing mutations of the MIE regulatory region. HCMV genome and its unique long (U L ) and short (U S ), internal repeat long (IR L ) and short (IR S ), terminal repeat long (TR L ) and short (TR S ), and a-sequence components are depicted. Locations of MIE regulatory region, MIE gene exons 1 to 4 (open boxes), and putative UL128 gene (open box) within U L component are shown. The MIE regulatory region of the WT is composed of proximal promoter (+1 to −64), enhancer (Enh; -65 to -550), unique region (-551 to -749), and modulator (Mod; -750 to -1140). Numerical base positions are assigned relative to start site of MIE RNAs. Recombinant HCMVs rΔ-300/-640 SVgfp , rΔ-300/-1108 SVgfp , rΔ-640/-1108 SVgfp , and r SVgfp were derived from rΔM SVgpt ). rΔ-300/-640 SVgfp , rΔ-300/-1108 SVgfp , and rΔ-640/-1108 SVgfp have deletions from -300 to -640, -300 to -1108, and -640 to -1108, respectively. An enhancerless SV40 early promoter (−138 to +57), gfp ORF, and SV40 early intron and polyadenylation signal were inserted at the site of deletion. r SVgfp has the same insertion at -640 but has no deletion. rΔM SVgpt has a deletion of -640 to -1108 and insertion of the SV40 early transcription unit containing the gpt ORF.
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