Poster abstracts

Poster number 89 submitted by Barsanjit Mazumder

Multifaceted role of ribosomal protein L13a during ribosome biogenesis, cellular IRES activity and translational silencing

Abhijit Basu (Cleveland State University), Ravinder Kour (Cleveland State University), Priyanka Das (Cleveland State University), Anton A. Komar (Cleveland State University), Barsanjit Mazumder (Cleveland State University)

Abstract:
2’-O-ribose of all ribosomal RNA (rRNA) is methylated and it is the most common covalent modification. Previously we showed a critical role of L13a in rRNA methylation and inhibition of rRNA methylation does not affect global protein synthesis in mammalian cells [1]. However, our subsequent studies identified a novel role of rRNA methylation for the translation of a cohort of Cellular Internal Ribosome Entry Sites (IRESs) [2]. Recently, using L13a protein as a model we have initiated a study investigating the mechanism of ribosomal protein incorporation in mammalian ribosome. This study has identified a critical residue of L13a essential for rRNA binding [3]. The extra-ribosomal activity of L13a in IFN-gamma induced translational silencing relies on its release from 60S ribosomal subunit. However, the mechanism of its release and how the released L13a assembled into the silencing competent RNA-binding complex and recognized by the target mRNAs harboring GAIT element in the 3’UTRs is poorly understood. To understand the specific domains or amino acid residues responsible for this diverse activity of a single ribosomal protein, we have conducted extensive deletion and mutational analysis of this protein. The result of this analysis shows significant insights about the diverse activity of this protein.

References:
[1]. Chaudhuri et al. RNA. 2007, 13(12): 2224-2237.
[2]. Basu et al. Mol. Cell. Biol. 2011, 31(2): 4482-4499.
[3]. Das et al. Mol. Cell. Biol. 2013, 33(15): 2829-2842.

Keywords: Ribosomal Protein L13a, Ribosome Biogenesis, Translational Silencing