title: Effects of in ovo electroporation on endogenous gene expression: genome-wide analysis.
abstract: BACKGROUND
  In ovo electroporation is a widely used technique to study gene function in developmental biology. Despite the widespread acceptance of this technique, no genome-wide analysis of the effects of in ovo electroporation, principally the current applied across the tissue and exogenous vector DNA introduced, on endogenous gene expression has been undertaken. Here, the effects of electric current and expression of a GFP-containing construct, via electroporation into the midbrain of Hamburger-Hamilton stage 10 chicken embryos, are analysed by microarray.
  
  
  RESULTS
  Both current alone and in combination with exogenous DNA expression have a small but reproducible effect on endogenous gene expression, changing the expression of the genes represented on the array by less than 0.1% (current) and less than 0.5% (current + DNA), respectively. The subset of genes regulated by electric current and exogenous DNA span a disparate set of cellular functions. However, no genes involved in the regional identity were affected. In sharp contrast to this, electroporation of a known transcription factor, Dmrt5, caused a much greater change in gene expression.
  
  
  CONCLUSIONS
  These findings represent the first systematic genome-wide analysis of the effects of in ovo electroporation on gene expression during embryonic development. The analysis reveals that this process has minimal impact on the genetic basis of cell fate specification. Thus, the study demonstrates the validity of the in ovo electroporation technique to study gene function and expression during development. Furthermore, the data presented here can be used as a resource to refine the set of transcriptional responders in future in ovo electroporation studies of specific gene function.
authors.affiliation: MRC Clinical Sciences Centre, Imperial College London, W12 0NN, UK. e.farley07@csc.mrc.ac.uk
authors.forename: Emma K
authors.initials: EK
authors.lastname: Farley
authors.forename: Emily
authors.initials: E
authors.lastname: Gale
authors.forename: David
authors.initials: D
authors.lastname: Chambers
authors.forename: Meng
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D001703:Biophysics; D002642:Chick Embryo; D019295:Computational Biology; D004558:Electric Stimulation / Q000379:methods; D018274:Electroporation / Q000379:methods; D015870:Gene Expression / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D016678:Genome / Q000235:genetics / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D008636:Mesencephalon / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D014157:Transcription Factors; D049452:Green Fluorescent Proteins