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Enzymes that metabolize RNA (ribonucleases, or RNases) play fundamental, primal roles in the living cell. If these ribonucleases malfunction, then mis-transcribed, mis-processed, mis-metabolized, or mis-sorted RNAs can have a severe impact on normal cellular function. Because all cellular RNAs are potential substrates for RNases and RNAs are omnipresent and multi-functional, local or global RNA defects can be an etiological agent of diseases and/or contribute to disease progression. Thus, understanding RNase structure and function may yield novel targets for therapeutic intervention.
We have two questions: How does the spatial and temporal control of RNase interactions and post-translational modifications relate to RNase recognition and metabolism of specific classes of RNAs in living cells? What are the catalytic mechanisms of RNases? To answer these questions, we are studying Dis3, Rrp6, and the ribonucleometabolic exosome. Dis3 is a processive, sequence-nonspecific 3’ to 5’ RNase that is homologous to eubacterial RNase R/II. Rrp6 is a distributive, sequence-nonspecific 3’ to 5’ RNase similar to eubacterial RNase D. The exosome is a multi-subunit complex or set of complexes that contain(s) putative RNases (Rrp41, Rrp42, Rrp43, Rrp45, Rrp46, Mtr3 are eukaryotic homologs of the eubacterial RNase PH) and the S1 RNA-binding domain proteins Rrp4, Rrp40, and Csl4. We have recently proposed and are testing the hypothesis that these subunits assemble into multiple independent, functionally interrelated complexes called exozymes.
We are currently using two model organisms (Drosophila melanogaster, Saccharomyces cerevisiae) and several approaches (cell biology, molecular biology, genetics, transcriptomics, bioinformatics, biochemistry) in our studies. This two-system, multi-disciplinary approach enhances the probability of discovering general principles and mechanisms underlying RNase activity in vitro and in vivo.
Selected Publications
Mamolen, M., Graham, A. C., Smith, A., Davis, S. M., and E. D. Andrulis. Dis3 domain analysis reveals functional links among subcellular targeting, dRrp6 and core exosome interactions, and ribonuclease activity. Under review at Journal of Biological Chemistry.
Mamolen, M. and E. D. Andrulis. Characterization of the Drosophila melanogaster Dis3 ribonuclease. Biochemical and Biophysical Research Communications, in press. [PubMed]
Kiss, D. L. and E. D. Andrulis. Genome-wide analysis reveals distinct substrate specificities of Dis3, Rrp6, and core exosome subunits. Submitted to RNA.
Smith, S.B., Tartakoff, A. M., and Andrulis, E.D. Pronounced and extensive microtubule defects in a Saccharomyces cerevisiae DIS3 mutant. Under review at Cell Motility and Cytoskeleton.
Graham, A. C., Kiss., D. L., and E. D. Andrulis (2009) Core exosome-independent roles for Drosophila Rrp6 in cell cycle progression. Molecular Biology of the Cell, 8:2242-53. [PubMed]
Graham, A.C., S. M. Davis, and E. D. Andrulis (2009) Interdependent nucleocytoplasmic trafficking and interactions of Dis3 with Rrp6, the core exosome, and importin-α3. Traffic, 10 (5): 499-513. [PubMed]
Graham, A.C., Kiss, D.L., and Andrulis E.D.. (2006) Differential Distribution of Exosome Subunits at the Nuclear Lamina and in Cytoplasmic Foci. Mol Biol Cell. 2006 Mar;17(3):1399-409. [PubMed]
Andrulis, E.D., Werner, J., Erdjument-Bromage, H., Nazarian, A., Tempst, P., and J. T. Lis. (2002) The RNA Processing Exosome is Linked to Elongating RNA Polymerase II in Drosophila. Nature, 420: 837-841. (Reviewed in Nat. Struc. Bio. 2003; 10: 10-12.) [PubMed]
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