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

Pre-rRNA processing in Saccharomyces cerevisiae. (A) Structure of the 35S primary transcript. Thick bars represent the mature 18S, 5.8S, and 25S rRNA sequences; thin lines, the spacer regions. Cleavage sites are indicated as are the location of the probes used for Northern and primer extension analysis. The gray bar corresponds to the in vitro transcript used in the binding experiments. (B) The pre-rRNA processing pathway.