Pol III binding in six mammals shows conservation among amino acid isotypes despite divergence among tRNA genes

Nat Genet. 2011 Aug 28;43(10):948-55. doi: 10.1038/ng.906.


RNA polymerase III (Pol III) transcription of tRNA genes is essential for generating the tRNA adaptor molecules that link genetic sequence and protein translation. By mapping Pol III occupancy genome-wide in mouse, rat, human, macaque, dog and opossum livers, we found that Pol III binding to individual tRNA genes varies substantially in strength and location. However, when we took into account tRNA redundancies by grouping Pol III occupancy into 46 anticodon isoacceptor families or 21 amino acid-based isotype classes, we discovered strong conservation. Similarly, Pol III occupancy of amino acid isotypes is almost invariant among transcriptionally and evolutionarily diverse tissues in mouse. Thus, synthesis of functional tRNA isotypes has been highly constrained, although the usage of individual tRNA genes has evolved rapidly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemistry*
  • Amino Acids / genetics
  • Animals
  • Anticodon / genetics
  • Chromatin Immunoprecipitation
  • Chromosome Mapping
  • Dogs
  • Evolution, Molecular
  • Gene Expression Regulation
  • Humans
  • Liver / metabolism
  • Macaca
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Oligonucleotide Array Sequence Analysis
  • Opossums
  • Protein Binding / genetics
  • RNA Polymerase III / genetics*
  • RNA Polymerase III / metabolism
  • RNA, Transfer / genetics*
  • RNA, Transfer / metabolism
  • Rats
  • Sequence Analysis, RNA
  • Transcription, Genetic
  • Transcriptome


  • Amino Acids
  • Anticodon
  • RNA, Transfer
  • RNA Polymerase III