The UL79 LTF initiates transcription at TATT-containing viral early-late and late promoters.

( A-C ) Genome browser views of PRO-Seq-Flavo results for TATTTAA-containing UL84 and UL85 promoters. Spike-in normalized reads from Pol II nascent transcripts are aligned to the HCMV TB40/E KF297339 genome. ( A ) HCMV TB40/E UL79 H F infection for 72 h treated with 6-h dTag vs. CTRL. ( B and C ) HCMV TB40/E WT infections for 12 and 48 h (in absence or presence of PFA). Panel C is a map of 5’-ends of the same reads aligned in panel B for 12-h and 48-h infections without PFA. Vertical arrows point to positions of UL84 and UL85 MAXTSS. ( D ) Scatterplot of PFA sensitivity index (PSI) vs. effect of UL79 H F LTF depletion on TSR strength (dTag vs. CTRL treatments) for 320 viral TSRs ≥435 nascent RNA reads (open circles). Viral TSRs having a TATT positioned -40 to -28 upstream of the MAXTSS are marked in red. PSI = ratio of TSR reads for PFA treatment/CTRL treatment of 72-h HCMV TB40/E WT infection. Effect of UL79 H F LTF depletion (dTag/CTRL reads) is described in Fig 3B . Dashed line denotes 0.5 dTag/CTRL read breakpoint. Arrows point to UL84 and UL85 TSRs, with PSIs 40 and 220, respectively.