Fig. 1

Different types of tRNA-derived RNA fragments produced from either pre-tRNAs or mature tRNAs. The 1-tRF series is produced by RNase Z (or ELAC2) cleavage of the pre-tRNA during the tRNA processing. Mature tRNA can be cleaved in the anticodon loop by ANG to produce 5′-tiRNA and 3′-tiRNA series under stress conditions. The 5′-tRF series is derived from the 5′-end of mature tRNAs by endonucleolytic cleavage and exonuclease digestion in the D-loop. The cleavage in the T-loop results in the production of the 3′-tRF series