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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. Thus, understanding ribonuclease 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 ribonucleases?
To answer these questions, we are studying three RNases: Dis3, Rrp6, and the ribonucleometabolic exosome (riboexosome). Dis3 is a processive, sequence-nonspecific 3’ to 5’ exoribonuclease that is homologous to eubacterial RNase R/II. Rrp6 is a distributive, sequence-nonspecific 3’ to 5’ exoribonuclease similar to eubacterial RNase D. The riboexosome 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. The eukaryotic riboexosome has recently been proposed to lack RNase activity; we are investigating this.
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 exoribonuclease activity in vitro and in vivo.
Selected Publications
Andrulis, E.D., Davis, S.M. and A. C. Graham. Interdependence of nucleocytoplasmic distribution and interactions of Dis3 with Rrp6, the core exosome, and importin-α3 Submitted
Graham, A.C., Kiss, D. L., and Andrulis, E.D. Dynamic redistribution of and functional requirement for Rrp6 in mitosis suggest exosome-independent roles in chromosome dynamics. Under revision.
Smith, S.B., Tartakoff, A. M., and Andrulis, E.D. Pronounced and extensive microtubule defects in a Saccharomyces cerevisiae DIS3 mutant. Submitted.
Hattier, T., Andrulis, E.D., and A. M. Tartakoff. Immobility, inheritance, and plasticity of shape of the yeast nucleus. BMC Cell Biology, in press.
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]
Adelman, K., Marr, M.T., Werner, J., Saunders, A., Ni, Z., Andrulis, E.D., and J.T. Lis (2005) Efficient release through the promoter-proximal stall sites requires transcript cleavage factor TFIIS. Molecular Cell 17:103-112. [PubMed]
Saunders, A., Werner, J., Andrulis, E.D., Nakayama, T., Hirose, S., Reinberg, D. and Lis, J. T. (2003) Tracking FACT and the RNA Polymerase II Elongation Complex Through Chromatin in vivo. Science, 301: 1094-1096. (Cover of Science; Perspective in Science, 301:1053-1054). [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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