Excision of the Frt-flanked neoR cassette from the CD19cre knock-in transgene reduces Cre-mediated recombination

Marc Schmidt-Supprian, F. Thomas Wunderlich, Klaus Rajewsky

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Intercross of mice transgenic for Flp-recombinase with the CD19cre mouse strain leads to excision of the Frt-flanked neoR cassette from the CD19cre knock-in transgene. This significantly reduces the expression level of Cre by the CD19cre transgene and consequently decreases the extent of Cre-mediated recombination of loxP-flanked alleles, most likely due to the fact that this neoR cassette contains polyoma enhancer sequences. We wish to draw attention to this finding, since the Flp-deleter mouse strain is commonly used to remove Frt-flanked selection cassettes in vivo from conditional alleles. Therefore conditional alleles have to be separated from the Flp-deleter transgene by breeding before crosses with CD19cre mice are initiated. In addition our findings suggest that gene expression from the CD19 locus can be increased by the insertion of exogenous enhancer sequences, without compromising B cell specificity.

Original languageEnglish
Pages (from-to)657-660
Number of pages4
JournalTransgenic Research
Volume16
Issue number5
DOIs
StatePublished - Oct 2007
Externally publishedYes

Keywords

  • B cells
  • CD19cre mouse stain
  • Conditional gene targeting efficiency
  • Frt-site flanked neomycin resistance gene cassette

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