Small Non-coding Transfer RNA-Derived RNA Fragments (tRFs): Their Biogenesis, Function and Implication in Human Diseases

Fu, Yu; Lee, Inhan; Lee, Yong Sun; Bao, Xiaoyong

Mature tRNAs are characterized by their evolutionarily conserved secondary and tertiary structures, extensive post-transcriptional modifications (up to 100 nucleoside modifications have been described), extreme stability and resistance to nucleases [20] [21] [22] . There are more than 600 tRNA genes in humans, which are far more than needed for at most 64 anticodons and 20 amino acids [23] [24] [25] , suggesting gene-specific functions of tRNAs other than its traditional function in linking a codon to the cognate amino acid during translation. Indeed, tRFs were recently identified as a new class of sncRNAs fragmentized from tRNAs and shown to be important in regulating cell proliferation, stress-induced translational suppression, stress granule (SG) assembly, and virus replication. Expression of some tRFs is commonly seen among different organisms, further supporting that tRFs have emerged as important players in diverse aspects of biology.