Association of Utp23 with snR30. (A) The UTP23 shuffle strain transformed with an empty LEU plasmid (Vector), or LEU plasmids expressing TAP-tagged Utp23 or indicated mutants were grown at 30°C. Cell extracts were centrifuged at 10,000g for 30 min (low speed) and additionally at 180,000g for 45 min to deplete large RNPs (high speed). Total cell lysates (TCL, 5%) and immunoprecipitations (IP) of IgG Sepharose were analyzed by Western blotting to detect Utp23-TAP and by Northern blotting with appropriate DNA probes to detect the indicated RNAs. (B) Quantification of snR30. snR10 is used as the internal loading reference because its amount appears to be consistent among different samples. The snR30 to snR10 ratio of Utp23 mutants is further normalized against that of wild-type Utp23 in the same treatment group.
