Poster abstracts
Poster number 45 submitted by Ernesto Roldan-Bonet
Understanding the role of nuclear/cytoplasmic dynamics in transfer RNA transport and quality control
Ernesto J. Roldan-Bonet (Department of Molecular Genetics, OSU), Paolo L. Sinopoli (Department of Molcular Genetics, OSU), Anita K. Hopper (Department of Molecular Genetics, Center for RNA Biology, OSU)
Abstract:
Transfer RNAs(tRNAs) are essential adaptor molecules that function in translation. Given their cytoplasmic function, tRNA subcellular movement was long thought to be unidirectional - from the nucleus to the cytoplasm. However, it is now well documented that cytoplasmic tRNAs are shuttled back into the nucleus via the tRNA retrograde nuclear import step before re-localizing to the cytoplasm via tRNA nuclear re-export. These latter trafficking events have been implicated in several important functions, for example, tRNA nuclear import plays a role in tRNA quality control as evidenced by the accumulation of hypomodified tRNAs in cells with impaired tRNA nuclear import. Both the fate of these aberrant tRNAs, and the proteins involved in nuclear import are largely unknown. We developed a genome-wide assay in Saccharomyces cerevisiae to identify proteins involved in the tRNA nuclear retrograde pathway taking advantage 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 aim to learn if tRNA nuclear import leads to the repair and/or destruction of aberrant tRNAs. To accomplish this, we performed genetic studies to assess the involvement of the tRNA retrograde pathway in conjunction with the Rapid tRNA Decay pathway and exosome RNases in quality control of aberrant tRNAs. Taken together, our studies will expand our understanding of tRNA nuclear trafficking and its involvement in tRNA quality control.
References:
1)Kramer, E. B., & Hopper, A. K. (2013). Retrograde transfer RNA nuclear import provides a new level of tRNA quality control in Saccharomyces cerevisiae. Proceedings of the National Academy of Sciences, 110(52), 21042–21047. https://doi.org/10.1073/pnas.1316579110
2)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
3)Phizicky, E. M., & Hopper, A. K. (2023). The life and times of a tRNA. https://doi.org/10.1261/rna
4)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, 102(32), 11290–11295. https://doi.org/10.1073/pnas.0503836102
Keywords: tRNA quality control, tRNA retrograde pathway, quality control pathways