Construction of the 6MIEpin1-DsRed-vOka genome. The varicella vaccine Oka strain (vOka)-BAC genome (A) is about 125-kbp long and includes terminal repeats (TRL and TRS), a unique long (UL) domain, internal repeats (IRL and IRS), and a unique short domain (US). The LacZα-mini-attTn7 sequence was inserted between ORF12 and ORF13 of the vOka-BAC genome by RecA-mediated recombination, generating vOka-BAC-Tn (B). The LacZα-mini-attTn7 sequence in the vOka-BAC-Tn genome permitted site-specific insertion of the HHV-6MIEpin1-DsRed-BGH poly(A) signal sequence casette (C) by Tn7-mediated transposition, resulting in the HHV-6MIEp-DsRed-vOka-BAC genome (D). Black arrowheads indicate the Bam HI sites. Horizontal bars indicate the region of the probe used for Southern blot analysis.