title: Lessons on conditional gene targeting in mouse adipose tissue.
abstract: Conditional gene targeting has been extensively used for in vivo analysis of gene function in adipocyte cell biology but often with debate over the tissue specificity and the efficacy of inactivation. To directly compare the specificity and efficacy of different Cre lines in mediating adipocyte specific recombination, transgenic Cre lines driven by the adipocyte protein 2 (aP2) and adiponectin (Adipoq) gene promoters, as well as a tamoxifen-inducible Cre driven by the aP2 gene promoter (iaP2), were bred to the Rosa26R (R26R) reporter. All three Cre lines demonstrated recombination in the brown and white fat pads. Using different floxed loci, the individual Cre lines displayed a range of efficacy to Cre-mediated recombination that ranged from no observable recombination to complete recombination within the fat. The Adipoq-Cre exhibited no observable recombination in any other tissues examined, whereas both aP2-Cre lines resulted in recombination in endothelial cells of the heart and nonendothelial, nonmyocyte cells in the skeletal muscle. In addition, the aP2-Cre line can lead to germline recombination of floxed alleles in ~2% of spermatozoa. Thus, different "adipocyte-specific" Cre lines display different degrees of efficiency and specificity, illustrating important differences that must be taken into account in their use for studying adipose biology.
authors: Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, USA.
authors: Kevin Y
authors: KY
authors: Lee
authors: Steven J
authors: SJ
authors: Russell
authors: Siegfried
authors: S
authors: Ussar
authors: Jeremie
authors: J
authors: Boucher
authors: Cecile
authors: C
authors: Vernochet
authors: Marcelo A
authors: MA
authors: Mori
authors: Graham
authors: G
authors: Smyth
authors: Michael
authors: M
authors: Rourk
authors: Carly
authors: C
authors: Cederquist
authors: Evan D
authors: ED
authors: Rosen
authors: Barbara B
authors: BB
authors: Kahn
authors: C Ronald
authors: CR
authors: Kahn
mesh_terms: D052242:Adiponectin / Q000235:genetics / Q000378:metabolism*; D000273:Adipose Tissue / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D003433:Crosses, Genetic; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D019426:Integrases / Q000235:genetics / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011995:Recombination, Genetic / Q000187:drug effects; D013629:Tamoxifen / Q000494:pharmacology; D019076:Transgenes / Q000187:drug effects; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D052242:Adiponectin; C499919:Adipoq protein, mouse; C493411:Fabp4 protein, mouse; D050556:Fatty Acid-Binding Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D013629:Tamoxifen; C045073:Cre recombinase; D019426:Integrases