Downstream U34 modification enzymes, ALKBH8 and CTU1, are essential for both SARS-CoV-2 and ZIKV replication—According to the U34 modification pathway (Figure 3B), alteration of the two enzymatic steps downstream of the Elongator complex (ELP1-6) step to generate mcm5s2U would also affect viral infection. Here, CTU1 is linked to viral infectious disease.