Germ line activation of the Tie2 and SMMHC promoters causes noncell-specific deletion of floxed alleles

WJ De Lange, CM Halabi, AM Beyer… - Physiological …, 2008 - journals.physiology.org
Physiological genomics, 2008journals.physiology.org
Tissue-specific knockouts generated through Cre-loxP recombination have become an
important tool to manipulate the mouse genome. Normally, two successive rounds of
breeding are performed to generate mice carrying two floxed target-gene alleles and a
transgene expressing Cre-recombinase tissue-specifically. We show herein that two
promoters commonly used to generate endothelium-specific (Tie2) and smooth muscle-
specific [smooth muscle myosin heavy chain (Smmhc)] knockout mice exhibit activity in the …
Tissue-specific knockouts generated through Cre-loxP recombination have become an important tool to manipulate the mouse genome. Normally, two successive rounds of breeding are performed to generate mice carrying two floxed target-gene alleles and a transgene expressing Cre-recombinase tissue-specifically. We show herein that two promoters commonly used to generate endothelium-specific (Tie2) and smooth muscle-specific [smooth muscle myosin heavy chain (Smmhc)] knockout mice exhibit activity in the female and male germ lines, respectively. This can result in the inheritance of a null allele in the second generation that is not tissue specific. Careful experimental design is required therefore to ensure that tissue-specific knockouts are indeed tissue specific and that appropriate controls are used to compare strains.
American Physiological Society