Talk abstracts

Talk on Saturday 10:10-10:25am submitted by Heather Woolls

Shining the Light on Dim2

Heather Woolls (Chemical Biology Doctoral Program, University of Michigan), Katrin Karbstsein (Department of Cancer Biology, Scripps-Florida)

Abstract:
In eukaryotes ribosome assembly requires hundreds of conserved essential proteins not present in the mature particle. Despite their importance, their function remains unknown. This is oftein because protein deletion affects the composition of the entire particle. Furthermore, many proteins appear to be present in assembling ribosomes for extended times making it difficult to pinpoint their role to a particular step. Here we have combined classical yeast biochemistry with experiments using recombinant proteins and RNA to study the role of Dim2, and its interaction with Nob1, the nuclease that generates the 3’-end of 18S rRNA. Analysis of Dim2 mutants in which the interaction with Nob1 is disrupted demonstrates that the interaction between Dim2 and Nob1 is essential. Furthermore, our data also indicate that Dim2 helps position Nob1 for correct cleavage at the 3’-end of 18S rRNA, as a point mutation that abolishes this interaction in vitro leads to accumulation of pre-ribosomes containing Nob1 and 20S rRNA. Interestingly, the site of interaction with Nob1 is mapped to a KH-like domain in Dim2, suggesting that this domain typically used for RNA binding can also be used as a protein-recognition motif.

Keywords: Ribosome Assembly, Dim2, KH domain