In addition, both LR and HR HPV E6/E7s, and SV40 large T antigen up-regulate UBC9 expression (Fig 4A and 4B) implying an activity of conserved relevance for the different virus life cycles, and p53 activity as well [54,55], further validating our hypothesis that poses UBC9 overexpression as a key feature during viral infections. Here, UBE2I is linked to viral infectious disease.