Figure 4.

FAM46B has PAP activity. (A) Test for CCA-adding activity for human FAM46B and mouse FAM46C. 10 μM 5′-biotinylated mini-tRNA primers with different 3′ tails as indicated were individually incubated with 10 μM protein in the presence of 2 mM ATP or CTP for 50 min. tmCCA was used as a positive control. (B) Polyadenylation activity for human FAM46B and mouse FAM46C. 10 μM 5′-biotinylated A₁₅ primer was incubated with 10 μM FAM46B or FAM46C in the presence of 4 mM Mg²⁺ or Mn²⁺ for 50 min. ATP was supplied with increasing concentrations as indicated.