Poster abstracts
Poster number 3 submitted by Nikolay Aleksashin
Processing of Ribo-T rRNA ends.
Nikolay A. Aleksashin (Center for Biomolecular Sciences, University of Illinois at Chicago), Alexander S. Mankin (Center for Biomolecular Sciences, University of Illinois at Chicago)
Abstract:
Correct processing of rRNA ends is one of the most important event of ribosome assembly. Ribo-T (ribosomes with tethered subunits) is built on a hybrid 16S/23S scaffold and its assembly is expected to deviate significantly from the normal ribosome biogenesis pathways. Therefore, the reason for the potential limitations of translational activity of Ribo-T could be the incorrect processing of rRNA ends. Moreover, because of the unique Ribo-T properties, this type of chimeric rRNA is an interesting model for studying the ribosome assembly. The main goal of this work is to examine the processing of the ends of Ribo-T rRNA.
By using 3’ RACE we observed that the processing of Ribo-T rRNA ends is less efficient in comparison with ribosomes with untethered subunits. A significant fraction of cellular Ribo-T carries 1-3 nt extensions at the 5’ end, whereas 3’ end of Ribo-T with the natural anti-Shine-Dalgarno (anti-SD) sequence is processed to the completion. Interestingly, altering the wild type anti-SD to a different sequence (the change required to generate an orthogonal translation system) resulted in the poorly processed 3’ ends. In this case a fraction of orthogonal Ribo-T carried 33 nt 3’ extensions.
Our results show that rRNA with significant perturbations of the structure or with unnatural sequences in a close proximity to the ends could still be processed, but less successfully.
Keywords: Ribo-T, rRNA, Processing