Figure 5. Binding characteristics of the Pop6/Pop7 heterodimer to the Tlc1 P3 domain in vitro and in vivo.
(A) Binding curves and apparent Kds of the Pop6/Pop7 heterodimer binding to indicated RNA oligonucleotides (see predicted structures, complete binding curve and gel assays in Figure S3). (B) Northern blot analysis of co-immunoprecipitated RNAs using IgG beads and extracts of strains that harbored TAP-tagged Pop7, a wt Tlc1 RNA and a 400 nt longer MS2-tagged Tlc1 RNA. The latter either contained a wt stem IVc, lanes 3–5; lacks the most distal stem-loop, MS2-tlc1-ΔS: lanes 6–8; or lacks the TeSS/P3 completely, MS2-tlc1-ΔL, lanes 9–11. IN: input (2.5%); IP: immunoprecipitates (10%); FT: flowthrough (2.5%). (C) Western blot of input (left) and immunoprecipitates (right) from strains harboring a Myc13-tagged Sme1 protein and Pop7-TAP. TCL1 alleles as indicated. See Figure S4A for predicted structures of the stem IVc in these mutated RNAs.