Fig 4.

(A) Genome-wide insertion profiling of the murine norovirus genome. Insertion sites detected in each passage (passage 1 [P1], passage 2 [P2], and passage 3 [P3]) for each library were compiled to generate a map of insertion sites across the entire genome, with the exception of the first 55 nt. A total of 2,089 insertions were detected in the input profile, with only 324 remaining after the three passages, indicating selection of viable mutants. Insertion sites found in the input and passage 3 populations at the end of NS4 (B) and the end of VP2 (C) are shown in greater detail. The insertions highlighted in red correspond to the position where a FLAG tag was later inserted in the NS4- and VP2-coding regions.