FIG. 6.
Yrap1 genetically and physically interacts with components of the exosome. (A) yra1ΔRBD is synthetically lethal with a mutation in RRP45. Strain sl5 (yra1ΔRBD rrp45-1 〈pCH1122-YRA1 URA ADE3〉) was transformed with empty vector or YRA1 and RRP45 gene constructs (pFS2525 and pFS2575). Transformants were streaked on 5-FOA as described for Fig. 1A. (B) Mutations in YRA1 are synthetically lethal with Δrrp6. The YRA1 shuffle (FSY1026) or YRA1 shuffle Δrrp6 (FSY1621) strains were transformed with vector or plasmids encoding wild-type or mutant Yra1p (LEU2 CEN). Transformants were streaked on 5-FOA plates and analyzed as described for panel A. (C) Yra1p physically interacts with components of the exosome. Total extracts were prepared from a nontagged strain (no tag) or strains expressing Rrp45-ProtA (FSY1476) or Rrp6-ProtA (FSY1657) and purified on IgG beads (lanes 1 to 6). Copurifying proteins were eluted with high levels of salt. Total extracts (input; lanes 1 to 3) or eluted proteins (eluates; lanes 4 to 6) were examined by Western blotting with antibodies against Yra1p and Hpr1p.