title: lck-Driven Cre Expression Alters T Cell Development in the Thymus and the Frequencies and Functions of Peripheral T Cell Subsets.
abstract: Conditional gene targeting using the bacteriophage-derived Cre recombinase is widely applied for functional gene studies in mice. Mice transgenic for Cre under the control of the lck gene promoter are used to study the role of loxP-targeted genes in T cell development and function. In this article, we show a striking 65% reduction in cellularity, preferential development of γδ versus αβ T cells, and increased expression of IL-7R in the thymus of mice expressing Cre under the proximal lck promoter (lck-cre(+) mice). The transition from CD4/CD8 double-negative to double-positive cells was blocked, and lck-cre(+) double-positive cells were more prone to apoptosis and showed higher levels of Cre expression. Importantly, numbers of naive T cells were reduced in spleens and lymph nodes of lck-cre(+) mice. In contrast, frequencies of γδ T cells, CD44(+)CD62L(-) effector T cells, and Foxp3(+) regulatory T cells were elevated, as was the frequency of IFN-γ-secreting CD4(+) and CD8(+) T cells. A literature survey of 332 articles that used lck-cre(+) mice for deletion of floxed genes indicated that results are statistically influenced by the control used (lck-cre(+) or lck-cre(-)), more frequently resembling the lck-cre(+) phenotype described in this article if lck-cre(-) controls were used. Altogether, care should be taken when interpreting published results and to properly control targeted gene deletions using the lck-cre(+) strain.
authors: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, S 171 77 Stockholm, Sweden; and Berit.Carow@ki.se.
authors: Berit
authors: B
authors: Carow
authors: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, S 171 77 Stockholm, Sweden; and.
authors: Yu
authors: Y
authors: Gao
authors: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, S 171 77 Stockholm, Sweden; and.
authors: Jonathan
authors: 0000-0002-5967-4857
authors: J
authors: Coquet
authors: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, S 171 77 Stockholm, Sweden.
authors: Marie
authors: M
authors: Reilly
authors: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, S 171 77 Stockholm, Sweden; and.
authors: Martin E
authors: ME
authors: Rottenberg
mesh_terms: D000818:Animals; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics; D017353:Gene Deletion; D019426:Integrases / Q000235:genetics / Q000378:metabolism*; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D020395:Receptors, Interleukin-7 / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
chemical_list: D020395:Receptors, Interleukin-7; D007371:Interferon-gamma; C000591805:Cilk1 protein, mouse; D017346:Protein Serine-Threonine Kinases; C045073:Cre recombinase; D019426:Integrases