FIGURE 6.

Rdn1 and Rdn2 are uridine-specific nucleotidyl transferases. (A) Products of nucleotidyl transferase assays using a 79-nt input ssRNA and purified RDRCs containing catalytic-dead Rdr1–D1004A. (B) Uridylation of a 79-nt input ssRNA by specific RDRCs. RDRCs were purified by the indicated tagged protein from extracts of cells that were starved (all lanes except 7,8) or at the 9-h time point of conjugation (lanes 7,8). The intensity of reaction product correlates with the level of Rdn present in the preparation (not shown). ZZ-Rdr1 was also purified from extracts of starved wild-type or gene knockout (KO) cells as noted.