Figure 2. Overlap of herpesviral protein-protein interaction networks.

(A) shows the sunflower structure induced by the protein sets of the five viruses and their intersections. For each overlapping area the number of shared proteins with detected interactions, in addition to the total number of shared proteins are indicated. All shared proteins in the various subgroups are interacting (with the exception of the β+γ subgroup where only three out of six shared proteins are interacting) while for the individual viruses between 50% and 70% of the proteins have observed interactions. (B) Comparison of conserved interactions between orthologous proteins for any two herpesvirus species. In each rectangle, the value above the lines indicates the observed number of homologous interactions detected in both herpesviruses (in green). The value below the line (in black) gives the total number of interactions detected in the first species (indicated in columns) between proteins which have orthologs in the second species (indicated in rows). On the diagonal, the total number of interactions is shown for each virus. (C) Distribution of the number of conserved interactions between HSV-1 and mCMV for 1000 random orthology assignments (blue line) in comparison to the true number of conserved interactions (red vertical line). For each pairwise comparison, subnetworks were selected between proteins conserved in both viruses and then the orthology assignments between the proteins were randomized. Accordingly, the size and degree distribution of the subnetworks does not change. (D) Comparison of the number of interactions conserved in 2, 3, 4 and 5 species for 1000 random orthology assignments (yellow boxes) to the true number of interactions conserved in that many viruses (red line). Random orthology assignments were created in a similar way as for Figure 2C.