Insertion of Cre into the Pax3 locus creates a new allele of Splotch and identifies unexpected Pax3 derivatives

Dev Biol. 2005 Apr 15;280(2):396-406. doi: 10.1016/j.ydbio.2005.02.002.


Pax3 is a transcription factor expressed in the dorsal neural tube and somite of the developing embryo. It plays critical roles in pre-migratory neural crest cells and in myogenic precursors of skeletal muscle. Pax3-deficient Splotch embryos display neural tube and neural crest defects and lack hypaxial muscles. We have created a new allele of Splotch by replacing the first coding exon with a gene encoding Cre recombinase. This functions as a null allele and no Pax3 protein is detected in homozygous embryos. Heterozygous Pax3(Cre/+) mice display a white belly spot, as do Splotch heterozygotes. Homozygous Pax3(Cre/Cre) embryos are embryonic lethal. We have used Pax3(Cre/+) mice to fate-map Pax3 derivatives in the developing mouse. As expected, neural crest and some somitic derivatives are identified. However, we also detect previously unappreciated derivatives of Pax3-expressing precursors in the colonic epithelium of the hindgut and within the urogenital system.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Animals
  • Cell Movement
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Embryo, Mammalian / metabolism
  • Exons
  • Genetic Techniques*
  • Genotype
  • Heterozygote
  • Homozygote
  • Immunoblotting
  • Immunohistochemistry
  • In Situ Hybridization
  • Mice
  • Mice, Transgenic
  • Models, Genetic
  • Muscle, Skeletal / cytology
  • Neurons / metabolism
  • PAX3 Transcription Factor
  • Paired Box Transcription Factors
  • RNA, Messenger / metabolism
  • Recombination, Genetic
  • Time Factors
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transcription, Genetic
  • beta-Galactosidase / metabolism


  • DNA-Binding Proteins
  • PAX3 Transcription Factor
  • Paired Box Transcription Factors
  • RNA, Messenger
  • Transcription Factors
  • Pax3 protein, mouse
  • beta-Galactosidase