Transcriptional activities of human elongation factor-1α and cytomegalovirus promoter in transgenic dogs generated by somatic cell nuclear transfer

PLoS One. 2020 Jun 3;15(6):e0233784. doi: 10.1371/journal.pone.0233784. eCollection 2020.

Abstract

Recent advances in somatic cell nuclear transfer (SCNT) in canines facilitate the production of canine transgenic models. Owing to the importance of stable and strong promoter activity in transgenic animals, we tested human elongation factor 1α (hEF1α) and cytomegalovirus (CMV) promoter sequences in SCNT transgenic dogs. After transfection, transgenic donor fibroblasts with the hEF1α-enhanced green fluorescence protein (EGFP) transgene were successfully isolated using fluorescence-activated cell sorting (FACS). We obtained four puppies, after SCNT, and identified three puppies as being transgenic using PCR analysis. Unexpectedly, EGFP regulated by hEF1α promoter was not observed at the organismal and cellular levels in these transgenic dogs. EGFP expression was rescued by the inhibition of DNA methyltransferases, implying that the hEF1α promoter is silenced by DNA methylation. Next, donor cells with CMV-EGFP transgene were successfully established and SCNT was performed. Three puppies of six born puppies were confirmed to be transgenic. Unlike hEF1α-regulated EGFP, CMV-regulated EGFP was strongly detectable at both the organismal and cellular levels in all transgenic dogs, even after 19 months. In conclusion, our study suggests that the CMV promoter is more suitable, than the hEF1α promoter, for stable transgene expression in SCNT-derived transgenic canine model.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Azacitidine / pharmacology
  • Cells, Cultured
  • Cloning, Organism / veterinary*
  • Cytomegalovirus / genetics*
  • DNA (Cytosine-5-)-Methyltransferases / antagonists & inhibitors
  • DNA Methylation / drug effects
  • Dogs
  • Embryo Transfer / veterinary
  • Female
  • Fibroblasts / metabolism
  • Gene Expression Regulation / drug effects
  • Green Fluorescent Proteins / genetics
  • Humans
  • Nuclear Transfer Techniques / veterinary*
  • Peptide Elongation Factor 1 / genetics*
  • Pregnancy
  • Promoter Regions, Genetic / genetics*
  • Transcriptional Activation / genetics*
  • Transfection
  • Transgenes

Substances

  • Peptide Elongation Factor 1
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • DNA (Cytosine-5-)-Methyltransferases
  • Azacitidine

Grants and funding

This work was supported by grants from the Next-Generation BioGreen21 Program (PJ01107701) and Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries(IPET) through Agri-Bio industry Technology Development Program from Ministry of Agriculture, Food and Rural Affairs (Grant number: 318016-5).