A growth-essential Tetrahymena Piwi protein carries tRNA fragment cargo

Genes Dev. 2010 Dec 15;24(24):2742-7. doi: 10.1101/gad.1996210. Epub 2010 Nov 24.


Argonaute/Piwi proteins associate with small RNAs that typically provide sequence specificity for RNP function in gene and genome regulation. Here we show that Twi12, a Tetrahymena Piwi protein essential for growth, is loaded with mature tRNA fragments. The tightly bound ~18- to 22-nucleotide tRNA 3' fragments are biochemically distinct from the tRNA halves produced transiently in response to stress. Notably, the end positions of Twi12-bound tRNA 3' fragments precisely match RNAs detected in total small RNA of mouse embryonic stem cells and human cancer cells. Our studies demonstrate unanticipated evolutionary conservation of mature tRNA processing to tRNA fragment small RNAs.

MeSH terms

  • Base Sequence
  • Biological Evolution
  • Protozoan Proteins / metabolism*
  • Protozoan Proteins / physiology
  • RNA Processing, Post-Transcriptional*
  • RNA, Transfer / metabolism*
  • Tetrahymena / genetics*
  • Tetrahymena / growth & development


  • Protozoan Proteins
  • RNA, Transfer

Associated data

  • GEO/GSE24916
  • GEO/GSM612779
  • GEO/GSM612780