title: Perinatal induction of Cre recombination with tamoxifen.
abstract: Temporal control of site-specific recombination is commonly achieved by using a tamoxifen-inducible form of Cre or Flp recombinases. Although powerful protocols of induction have been developed for gene inactivation at adult stages or during embryonic development, induction of recombination at late gestational or early postnatal stages is still difficult to achieve. In this context, using the ubiquitous CMV-CreER(T2) transgenic mice, we have tested and validated two procedures to achieve recombination just before and just after birth. The efficiency of recombination was evaluated in the brain, which is known to be more problematic to target. For the late gestation treatment with tamoxifen, different protocols of complementary administration of progesterone and estrogen were tested. However, delayed delivery and/or mortality of pups due to difficult delivery were always observed. To circumvent this problem, pups were collected from tamoxifen-treated pregnant dams by caesarian section at E18.5 and given to foster mothers. For postnatal treatment, different dosages of tamoxifen were administered by intragastric injection to the pups during 3 or 4 days after birth. The efficiency of these treatments was analyzed at P7 using a transgenic reporter line. They were also validated with the Hoxa5 conditional allele. In conclusion, we have developed efficient procedures that allow achieving efficient recombination of floxed alleles at perinatal stages. These protocols will allow investigating the late/adult functions of many developmental genes, whose characterization has been so far restricted to embryonic development.
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
authors.forename: Benoit
authors.initials: B
authors.lastname: Lizen
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.|Institut de Duve, Université catholique de Louvain, 1200, Woluwe-Saint-Lambert, Belgium.
authors.forename: Melissa
authors.initials: M
authors.lastname: Claus
authors.affiliation: Department of Molecular Biology, Medical Biochemistry and Pathology, Université Laval, Québec, Canada.|Centre de recherche sur le cancer de l'Université Laval, Québec, Canada.|CRHDQ, L'Hôtel-Dieu de Québec, Québec, Canada.
authors.forename: Lucie
authors.initials: L
authors.lastname: Jeannotte
authors.affiliation: Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland.
authors.forename: Filippo M
authors.initials: FM
authors.lastname: Rijli
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium. Francoise.Gofflot@uclouvain.be.
authors.forename: Françoise
authors.initials: F
authors.lastname: Gofflot
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics*; D019426:Integrases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008822:Mice, Transgenic; D018743:Perinatal Care; D010750:Phosphoproteins / Q000235:genetics*; D011247:Pregnancy; D011960:Receptors, Estrogen / Q000235:genetics*; D011995:Recombination, Genetic; D013629:Tamoxifen / Q000494:pharmacology*; D014157:Transcription Factors
chemical_list: D004965:Estrogen Antagonists; D018398:Homeodomain Proteins; C059637:Hoxa5 protein, mouse; D010750:Phosphoproteins; D011960:Receptors, Estrogen; D014157:Transcription Factors; D013629:Tamoxifen; C045073:Cre recombinase; D019426:Integrases
keywords: Conditional mutagenesis; CreERT2; Hoxa5; Site-specific recombinase; Tomato reporter line