Figure 2. Binding of the Pop1/Pop6/Pop7 proteins to the Tlc1 RNA is specific.

(A) Northern analysis of immunoprecipitations using IgG covered beads with extracts from strains expressing the indicated TAP-tagged proteins. For the HA₃-Pop1, anti-HA antibodies were used. The blots were hybridized with probes specific for the Tlc1 RNA and the Nme1 RNA at the same time. Ctrl RNAs on left: total RNAs from a wt strain or a strain that carried a tlc1Δ allele. IN: RNA from the input fraction IP: RNA from the immunoprecipitates; FT: RNA extracted from the unbound fraction. (B) Northern analysis as performed in panel (A). (C) Telomerase activity enrichment using a tagged Pop1, Pop6, or Pop7 protein. Top: antibodies used for immunoprecipitations with extracts derived from strains harboring the indicated tagged proteins. ProA-Est2 serves as positive control. Note that direct and indirect anti-HA refers to whether the anti-HA antibody was directly coupled to magnetic beads or whether antibody was first mixed with the slurry and then immunopurified with Protein A/G coupled magnetic beads. For the HA-tagged Pop1 protein, the latter technique appears more efficient in telomerase recuperation. Labeling as in Figure 1B. See also Figure S1B.