Abstract
Human cytoplasmic tRNAs contain dihydrouridine modifications at positions 16 and 17 (D16/D17). The enzyme responsible for D16/D17 formation and its cellular roles remain elusive. Here, we identify DUS1L as the human tRNA D16/D17 writer. DUS1L knockout in the glioblastoma cell lines LNZ308 and U87 causes loss of D16/D17. D formation is reconstituted in vitro using recombinant DUS1L in the presence of NADPH or NADH. DUS1L knockout/overexpression in LNZ308 cells shows that DUS1L supports cell growth. Moreover, higher DUS1L expression in glioma patients is associated with poorer prognosis. Upon vector-mediated DUS1L overexpression in LNZ308 cells, 5' and 3' processing of precursor tRNAis inhibited, resulting in a reduced mature tRNAlevel, reduced translation of the tyrosine codons UAC and UAU, and reduced translational readthrough of the near-cognate stop codons UAA and UAG. Moreover, DUS1L overexpression increases the amounts of several D16/D17-containing tRNAs and total cellular translation. Our study identifies a human dihydrouridine writer, providing the foundation to study its roles in health and disease.
Overview
- The study investigates the enzyme responsible for dihydrouridine modifications at positions 16 and 17 (D16/D17) in human cytoplasmic tRNAs. The study identifies DUS1L as the human tRNA D16/D17 writer. The study aims to understand the cellular roles of DUS1L and its impact on cell growth and translation in glioblastoma cells. The study uses knockout and overexpression of DUS1L in LNZ308 and U87 glioblastoma cell lines to investigate its effects on cell growth and translation. The study also investigates the effects of DUS1L overexpression on precursor tRNA processing, mature tRNA levels, and translation readthrough of near-cognate stop codons. The study aims to provide the foundation to study the roles of DUS1L in health and disease.
Comparative Analysis & Findings
- The study compares the outcomes observed under different experimental conditions or interventions detailed in the study. The study identifies DUS1L as the human tRNA D16/D17 writer. D formation is reconstituted in vitro using recombinant DUS1L in the presence of NADPH or NADH. DUS1L knockout/overexpression in LNZ308 cells shows that DUS1L supports cell growth. Moreover, higher DUS1L expression in glioma patients is associated with poorer prognosis. Upon vector-mediated DUS1L overexpression in LNZ308 cells, 5' and 3' processing of precursor tRNAis inhibited, resulting in a reduced mature tRNAlevel, reduced translation of the tyrosine codons UAC and UAU, and reduced translational readthrough of the near-cognate stop codons UAA and UAG. Moreover, DUS1L overexpression increases the amounts of several D16/D17-containing tRNAs and total cellular translation. The study identifies significant differences in the results between the conditions, such as the loss of D16/D17 formation in DUS1L knockout cells and the inhibition of precursor tRNA processing in DUS1L overexpression cells. The study also discusses the key findings of the study and how they relate to the initial hypothesis, such as the identification of DUS1L as the human tRNA D16/D17 writer and its impact on cell growth and translation in glioblastoma cells.
Implications and Future Directions
- The study explains the significance of the study's findings and their potential impact on the field of research or clinical practice. The study identifies DUS1L as the human tRNA D16/D17 writer, providing the foundation to study its roles in health and disease. The study also identifies the impact of DUS1L on cell growth and translation in glioblastoma cells. The study suggests possible future research directions that could build on the results of the study, explore unresolved questions, or utilize novel approaches, such as studying the role of DUS1L in other cell types or investigating its interaction with other proteins involved in tRNA processing and translation. The study also identifies limitations of the study that need to be addressed in future research, such as the need for more extensive studies in animal models or human tissues to validate the findings in vivo.