Extended Data Fig. 1: High-resolution HCMV tiling screen.

a, Data processing for the HCMV tiling screen. We calculated log₂ ratios of each individual sgRNA in the surviving over the t₀ populations, averaged across two biological replicates. Ratios were averaged in a sliding 250 bp window. The average of the ratios of the non-targeting sgRNA population was set as the baseline. The plot was then colored based on the sign of the average phenotype and layered in bands of decreasing lightness, one log₂ unit wide. The negative space was mirrored on the baseline, and bands were stacked for the final horizon plot representation⁶⁶. b, High-resolution horizon graph of the phenotypic landscape of the HCMV genome. Shades of blue denote sensitization to host cell death, shades of red denote protection from cell death upon HCMV genome cleavage. Major features of the HCMV genome are annotated. sgRNAs targeting internal and terminal repeat regions (hashed) typically have multiple target sites and likely result in higher-order fragmentation of the HCMV genome, exacerbating their respective phenotypes. Viral ORFs are classified by their essentiality for viral replication based on ref. ¹⁰. ORFL150C, ORFL151C (originally named UL59, but thought to not be expressed as a protein⁶⁷, causing it to be dropped from the consensus annotation), and ORFL152C were the only short ORFs with strong phenotypes in areas of the genome devoid of consensus genes. UL48 was the only gene that showed a substantial phenotype gradient within its gene body: Cutting the N-terminal region caused mild sensitization to death upon infection, whereas cutting the C-terminus had the opposite effect.