3tRF

3tRF, short for 3' tRNA-derived fragment, is a class of small non-coding RNAs that originate from the 3' end of mature tRNAs. As a subset of the tRNA-derived fragment (tRF) family, 3tRFs are typically 18–22 nucleotides long and often retain the 3' CCA tail characteristic of mature tRNAs.

Biogenesis and features: 3tRFs are generated by endonucleolytic cleavage within the 3' region of mature tRNA, and production is enhanced under cellular stress. Enzymes implicated in their formation include Dicer, angiogenin, and RNase Z, though pathways vary by organism. They frequently carry nucleotide modifications and can associate with Argonaute proteins in some contexts, suggesting integration into small RNA pathways.

Functions: 3tRFs participate in post-transcriptional regulation, often in a miRNA-like manner by guiding Argonaute complexes to target mRNAs to influence stability or translation. Other reported roles include regulation of protein synthesis and cellular stress responses; functions are tissue- and species-specific.

Occurrence and significance: 3tRFs have been observed in plants, animals, and fungi, with changes in abundance under stress and disease. They are of interest as potential biomarkers and therapeutic targets, and are analyzed in small RNA sequencing studies.

Detection and resources: Identification uses small RNA sequencing, Northern blotting, and qPCR. Databases such as tRFdb and MINTbase provide annotations for tRNA-derived fragments, including 3' fragments, to support research.