In vivo measurements reveal a single 5'-intron is sufficient to increase protein expression level in Caenorhabditis elegans

Sci Rep. 2019 Jun 24;9(1):9192. doi: 10.1038/s41598-019-45517-0.


Introns can increase gene expression levels using a variety of mechanisms collectively referred to as Intron Mediated Enhancement (IME). IME has been measured in cell culture and plant models by quantifying expression of intronless and intron-bearing reporter genes in vitro. We developed hardware and software to implement microfluidic chip-based gene expression quantification in vivo. We altered position, number and sequence of introns in reporter genes controlled by the hsp-90 promoter. Consistent with plant and mammalian studies, we determined a single, natural or synthetic, 5'-intron is sufficient for the full IME effect conferred by three synthetic introns, while a 3'-intron is not. We found coding sequence can affect IME; the same three synthetic introns that increase mcherry protein concentration by approximately 50%, increase mEGFP by 80%. We determined IME effect size is not greatly affected by the stronger vit-2 promoter. Our microfluidic imaging approach should facilitate screens for factors affecting IME and other intron-dependent processes.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 5' Untranslated Regions*
  • Animals
  • Animals, Genetically Modified / genetics
  • Caenorhabditis elegans / genetics*
  • Gene Expression
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Genetic Enhancement*
  • Green Fluorescent Proteins / biosynthesis
  • Green Fluorescent Proteins / genetics
  • Introns*
  • Luminescent Proteins / biosynthesis
  • Luminescent Proteins / genetics
  • Promoter Regions, Genetic


  • 5' Untranslated Regions
  • Luminescent Proteins
  • enhanced green fluorescent protein
  • red fluorescent protein
  • Green Fluorescent Proteins