Poster abstracts
Poster number 162 submitted by Ernesto Roldan-Bonet
Genome-wide application of a tRNA assay to uncover proteins involved in the tRNA nuclear retrograde pathway
Ernesto J. Roldan-Bonet (Department of Molecular Genetics, OSU), Paolo L. Sinopoli (Department of Molcular Genetics, OSU), Bianca Lederfeind (Department of Biochemistry and Molecular Biology, UF), Anita K. Hopper (Department of Molecular Genetics, OSU)
Abstract:
Transfer RNAs(tRNAs) are initially transcribed in the nucleus and subsequently transported to the cytoplasm where they function as essential adaptor molecules in translation. Given their cytoplasmic function, tRNA subcellular trafficking was thought to be unidirectional – from the nucleus to the cytoplasm. It is now well documented that after primary nuclear export, tRNAs are shuttled back into the nucleus in a process called retrograde tRNA nuclear import before re-localizing to the cytoplasm (tRNA nuclear re-export). These latter trafficking steps have been implicated in several important functions, yet our understanding of the proteins involved is incomplete. Here, we developed a genome-wide assay in Saccharomyces cerevisiae to identify proteins involved in the tRNA nuclear retrograde pathway via the detection of the retrograde pathway-dependent, post-transcriptional tRNA modification: wybutosine (yW). Over 15% of the annotated genome has been queried, and we have identified three proteins involved in yW biosynthesis – validating our unbiased approach. Additionally, we queried all the members of the karyopherin-beta family, which comprise several nuclear exportins, importins and biportins, representing the largest known family of tRNA nuclear transporters. Taken together, our studies aim to identify the missing proteins involved in the widely conserved tRNA nuclear retrograde pathway.
References:
Nostramo, R. T., & Hopper, A. K. (2020). A novel assay provides insight into tRNAPhe retrograde nuclear import and re-export in S. cerevisiae. Nucleic acids research, 48(20),11577–11588. https://doi.org/10.1093/nar/gkaa879
Shaheen, H. H., & Hopper, A. K. (2005). Retrograde movement of tRNAs from the cytoplasm to the nucleus in Saccharomyces cerevisiae. Proceedings of the National Academy of Sciences of the United States of America, 102(32), 11290–11295. https://doi.org/10.1073/pnas.0503836102
Takano, A., Kajita, T., Mochizuki, M., Endo, T., & Yoshihisa, T. (2015). Cytosolic Hsp70 and co-chaperones constitute a novel system for tRNA import into the nucleus. eLife, 4, e04659. https://doi.org/10.7554/eLife.04659
Keywords: tRNA retrograde pathway, subcellular trafficking, wybutosine