Fig. 1

Different types of tRNA derivatives came from the cleavage of pre-tRNAs and mature tRNAs. tsRNAs were generated in the nucleus as a consequence of the pre-tRNA 3′ end cleavage. tiRNAs were generated as a consequence of angiogenin cleaving the anti-codon loop of the mature tRNA. tRFs were formed by Dicer at D-loop, T-loop and other positions of the nucleic acid ribozyme through cleavage of the mature tRNA