Figure 4.

Oxidative stress boosts tiRNA production through inhibition of the RTCB ligase complex. (A,B) H₂O₂ treatment boosts sodium arsenite-induced tiRNA production. U2OS cells were treated with 500 µM of sodium arsenite and/or 1 mM of H₂O₂ for 2 h. (A) SYBR Gold staining and (B) Northern blotting for tRNA^Gly-GCC and tRNA^iMet-CAT. Canonical 5′-tiRNAs are indicated by arrowheads, while a non-canonical 5′-tiRNA^iMet-CAT is indicated by a blue arrowhead. The amounts of 5′-tiRNAs calculated by densitometry are also shown (n = 4 each). (C,D) Effect of the combination between menadione (at 100 µM) and sodium arsenite (at 500 µM) on tiRNA production. (C) SYBR Gold and (D) Northern blotting for tRNA^Gly-GCC, tRNA^iMet-CAT and tRNA^Tyr-GTA. tiRNAs are indicated by red arrowheads. SA, sodium arsenite; Mena., menadione.