Stress-induced tRNA-derived RNAs (tiRNAs) (named also tRNA halves), found in diverse eukaryotes, are generated by endonucleolytic cleavage in the anticodon loop of mature tRNAs, catalyzed by angiogenin in mammals [PMID: 19332886, 19114040]. Under normal conditions, angiogenin is inhibited by binding to RNH1 [PMID: 19332886].

tRNA cleavage is induced by various stress conditions, such as nutrition deficiency, hypoxia and hypothermia or arsenite, heat shock, or ultraviolet irradiation.