Highly efficient transgene-independent recombination directed by a maternally derived SOX2CRE transgene

The Cre/loxP site-specific recombination system is a powerful tool that allows gene inactivation in a tissue- and time-specific manner. Several reports have shown that the Sox2Cre transgenic strain provides a very efficient means to delete gene function from the early epiblast (Hayashi et al.: Gene Expr Patterns 2:93-97, 2002; Vincent et al.: Genes Dev 17:1646-1662, 2003). Routinely, male studs carrying one null allele of the gene of interest and the Cre transgene are crossed to females homozygous for the conditional allele. Normally, excision is observed only in the progeny inheriting both the Cre transgene and the conditional allele. Here we report that when the Sox2Cre transgene is inherited maternally, excision occurs in all offspring irrespective of whether they carry the Cre transgene. Thus, Sox2Cre females provide a generally useful tool for rapid and efficient removal of loxP flanked sequences in vivo.