Rrp5p, a trans-acting factor in yeast ribosome biogenesis, is an RNA-binding protein with a pronounced preference for U-rich sequences

In vitro RNA binding by Rrp5p. ³²P-UTP-labeled, in vitro transcribed RNA fragments were incubated with IgG Sepharose beads loaded with ProtA-Rrp5p. (Bars 1,2) ITS1 fragment (cf. Fig. 1A); (bars 3,4) fragment transcribed from plasmid pBKS. (Gray bars) Control beads prepared with extract from cells expressing untagged Rrp5p; (black bars) beads prepared with extract from cells expressing tagged Rrp5p. Binding is expressed as the percentage of the input radioactivity retained by the beads.