Figure 6.

Each component of the Rpf2 subcomplex assembles into 90S preribosomes. (A) Whole-cell extracts were prepared from an untagged strain (JWY6147) and Rpf2-TAP (JWY7087) and Rrs1-TAP (JWY7461) strains. RNA was extracted from whole-cell extracts (left) and affinity-purified samples (right). Five micrograms of total RNA and 100% of purified RNA were used to assay 35S, 27SA₂, and 27SB pre-rRNAs by primer extension. Amounts of 27SA₃ pre-rRNA were very low and thus are invisible in some lanes. No pre-rRNAs copurified upon mock purification from untagged strains. Note that different oligos were used in reactions for 35S and 27S pre-rRNAs, and longer exposure was done for 35S pre-rRNA. (B) Preribosomes were affinity-purified using TAP-tagged Nop7. Purified pre-rRNPs containing rpL5-HA3 or rpL11 were immunoprecipitated by anti-HA antiserum. Five micrograms of total RNA (left) and 100% of purified RNA (right) were assayed for 35S, 27SA₂, 27SA₃, and 27SB pre-rRNAs by primer extension. Pre-rRNPs from an untagged strain were used as a negative control.