Tissue- and Time-Specific Expression of Otherwise Identical tRNA Genes

PLoS Genet. 2016 Aug 25;12(8):e1006264. doi: 10.1371/journal.pgen.1006264. eCollection 2016 Aug.

Abstract

Codon usage bias affects protein translation because tRNAs that recognize synonymous codons differ in their abundance. Although the current dogma states that tRNA expression is exclusively regulated by intrinsic control elements (A- and B-box sequences), we revealed, using a reporter that monitors the levels of individual tRNA genes in Caenorhabditis elegans, that eight tryptophan tRNA genes, 100% identical in sequence, are expressed in different tissues and change their expression dynamically. Furthermore, the expression levels of the sup-7 tRNA gene at day 6 were found to predict the animal's lifespan. We discovered that the expression of tRNAs that reside within introns of protein-coding genes is affected by the host gene's promoter. Pairing between specific Pol II genes and the tRNAs that are contained in their introns is most likely adaptive, since a genome-wide analysis revealed that the presence of specific intronic tRNAs within specific orthologous genes is conserved across Caenorhabditis species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans Proteins / genetics
  • Codon / genetics
  • Gene Expression Regulation
  • Genome
  • Introns / genetics*
  • Longevity / genetics
  • Organ Specificity / genetics
  • Promoter Regions, Genetic / genetics
  • Protein Biosynthesis / genetics*
  • RNA, Transfer / biosynthesis
  • RNA, Transfer / genetics*

Substances

  • Caenorhabditis elegans Proteins
  • Codon
  • RNA, Transfer

Grant support

This work was supported by ERC grant #335624 to OR. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.