Artefactual gene induction during preparation of Xenopus laevis animal cap explants

Int J Dev Biol. 1999 Sep;43(6):563-6.


The animal cap assay in Xenopus laevis was used to study the induction and regulation of the mesoderm-specific gene Xegr-1, a homolog of the mammalian egr-1 genes. Egr-1 is an immediate-early gene whose growth factor-stimulated transcriptional induction displays a transient activity profile and occurs independent of protein synthesis. The Xegr-1 promoter contains multiple serum response elements (SREs). In this paper we show that Xegr-1 is induced unspecifically during the process of animal cap preparation. Transcripts of Xegr-1 appear already 30 min after cutting of animal caps. Xfos, another SRE-regulated immediate-early gene, is induced with the same kinetics as Xegr-1. In contrast, the Xbra gene is not induced under the experimental conditions used. Xfos and Xegr-1 transcripts are not rapidly down-regulated after mechanical stimulation, but can be detected for up to 4 h later. Wounding-dependent Xegr-1 induction is reduced by injection of either mRNA coding for the dominant inhibitory forms of both the FGF receptor and the transcription factor Elk-1. Xegr-1 expression can be reinduced by mesoderm-inducing factors. These results led us to develop a new protocol for animal cap preparation, which circumvents the observed undesired artefactual gene activation events.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Artifacts*
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / metabolism*
  • Dissection / adverse effects*
  • Early Growth Response Protein 1
  • Embryo, Nonmammalian
  • Immediate-Early Proteins / metabolism*
  • Proto-Oncogene Proteins / metabolism
  • Response Elements
  • T-Box Domain Proteins / metabolism
  • Transcription Factors / biosynthesis
  • Transcription Factors / metabolism*
  • Xenopus Proteins*
  • Xenopus laevis
  • ets-Domain Protein Elk-1


  • DNA-Binding Proteins
  • EGR1 protein, Xenopus
  • Early Growth Response Protein 1
  • Immediate-Early Proteins
  • Proto-Oncogene Proteins
  • T-Box Domain Proteins
  • TBXT protein, Xenopus
  • Transcription Factors
  • Xenopus Proteins
  • ets-Domain Protein Elk-1