Knock-in of diphteria toxin A chain gene at Ins2 locus: effects on islet development and localization of Ins2 expression in the brain

Transgenic Res. 2004 Oct;13(5):463-73. doi: 10.1007/s11248-004-9587-x.


We report here knock-in of diphteria toxin A chain (dta) gene at the Ins2 locus, using the strategy previously employed to insert lacZ under control of the Ins2 promoter. Mutant Ins2(dta/+), Ins2(dta/lacZ) or Ins2(lacZ/+) mouse pups were generated by breeding and analyzed to study the effects of toxigenetic beta-cell ablation on islet development and to localize the extrapancreatic Ins2 expression site in the brain. Ins2(dta/+) and Ins2(dta/lacZ) pups developed a severe diabetic ketoacidosis and died rapidly. Histological analysis of their pancreas revealed that beta-cells completely disappeared in their islets as evidenced by loss of lacZ activity or insulin immunonostaining. beta-cell ablation did not alter the size of other islet cell populations which were normal at birth, although the glucagon-cell population was reduced by 85% at embryonic day E12.5. In the brain, comparative analysis of lacZ expression in Ins2(lacZ/+) and Ins2(dta/laZ) mice identified the choroid plexus (CP) as a major Ins2 expression site. This finding was confirmed by RT-PCR analysis of insulin transcripts in RNAs prepared from microdissected wild-type CP. Transcripts for other key beta-cell markers, with the notable exception of Pdx-1, were also found in CP RNAs. These results must revive interest in studies focused on extrapancreatic insulin gene expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Choroid Plexus / metabolism*
  • Choroid Plexus / pathology
  • Diabetic Ketoacidosis / metabolism
  • Diabetic Ketoacidosis / pathology
  • Diphtheria Toxin / genetics*
  • Diphtheria Toxin / metabolism
  • Gene Expression Regulation, Developmental*
  • Genetic Vectors / genetics
  • Insulin / metabolism
  • Islets of Langerhans / metabolism*
  • Islets of Langerhans / pathology
  • Lac Operon / genetics
  • Mice
  • Mice, Transgenic
  • Pancreas / metabolism*
  • Pancreas / pathology
  • Peptide Fragments / genetics*
  • Peptide Fragments / metabolism
  • Promoter Regions, Genetic


  • Diphtheria Toxin
  • Insulin
  • Peptide Fragments
  • diphtheria toxin fragment A