NMR STUDY OF NRD1 AND ITS BINDING TO RNA
V. Bačíková1, M. Zimmermann2, R. Štefl1
1 National Centre for Biomolecular Research
2 Institute of Experimental Biology
Masaryk University, Faculty of Science, 611 37 Brno, Czech Republic
The exosome - a complex of several exoribonucleolytic and RNA-binding proteins - is the central 3'-end RNA degradation and processing factor in RNA quality control apparatus. It operates with many auxiliary factors that stimulate its activity and recruit its RNA substrates in the crowded cellular environment. One of this factor is the nuclear pre-mRNA down-regulation (Nrd)1 complex, which consists of the RNA helicase Sen1, and the proteins Nrd1 and nuclear polyadenylated RNA-binding (Nab)3 that recognize specific sequence motifs on RNAs. This complex is required for transcription termination of small nuclear RNA and small nucleolar RNA genes as well as for cryptic unstable transcripts. Nrd1 protein contains RNA-recognition motif (RRM) that is known to bind its specific terminator sequence, GUA[A/G].
We will present a nuclear magnetic resonance (NMR) chemical shift perturbation and fluorescence anisotropy studies of the interaction of Nrd1 RRM with its RNA target. These studies reveal RNA-binding interface of Nrd1 and its affinity to the 5’-GUAA-3’ RNA.