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Vol 54(2020) N 3 p. 396-401; DOI 10.1134/S0026893320030188 I. Uluisik1,2, H.С Karakaya1, A. Koc1,3* tRNA Wobble Base Modifications and Boric Acid Resistance in Yeast: Boron-Resistant Deletion Mutants Induce the General Amino Acid Control Mechanism and Activate Boron Efflux 1Department of Molecular Biology and Genetics, Izmir Institute of Technology, Izmir, 35430 Turkey2Department of Biomedical Engineering, Iskenderun Technical University, Hatay, 31200 Turkey 3Department of Genetics, Inonu University School of Medicine, Malatya, 44280 Turkey *ahmet.koc@inonu.edu.tr Received - 2019-09-19; Revised - 2019-10-19; Accepted - 2019-10-21 Boric acid is essential for plants and has many vital roles in animals and microorganisms. However, its high doses are toxic to all organisms. We previously screened yeast deletion collections to identify boric acid-resistant and susceptible mutants to identify genes that play a role in boron tolerance. Here, we analyzed boron resistant mutants (elplΔ, elp3Δ, elp6Δ, ncs2Δ, ncs6Δ and ktil2Δ) for their abilities to modulate the general amino acid control system (GAAC) and to induce boron efflux pump ATR1. The mutants analyzed in this study lack the genes that play roles in tRNA Wobble base modifications. We found that all of the boron resistant mutants activated Gcn4-dependent reporter gene activity and increased the transcript level of the ATR1 gene. Additionally, boron resistant cells accumulated less boric acid in their cytoplasm compared to the wild type cells upon boron exposure. Thus, our findings suggested that loss of wobble base modifications in tRNA leads to GAAC activation and ATR1 induction, which in turn reduced intracellular boron levels and caused boron resistance. boron, boric acid, tRNA, Wobble base, boron resistance, elongator complex, yeast, general amino acid control |