title: Preferential activation of an IL-2 regulatory sequence transgene in TCR gamma delta and NKT cells: subset-specific differences in IL-2 regulation.
abstract: A transgene with 8.4-kb of regulatory sequence from the murine IL-2 gene drives consistent expression of a green fluorescent protein (GFP) reporter gene in all cell types that normally express IL-2. However, quantitative analysis of this expression shows that different T cell subsets within the same mouse show divergent abilities to express the transgene as compared with endogenous IL-2 genes. TCR gamma delta cells, as well as alpha beta TCR-NKT cells, exhibit higher in vivo transgene expression levels than TCR alpha beta cells. This deviates from patterns of normal IL-2 expression and from expression of an IL-2-GFP knock-in. Peripheral TCR gamma delta cells accumulate GFP RNA faster than endogenous IL-2 RNA upon stimulation, whereas TCR alpha beta cells express more IL-2 than GFP RNA. In TCR gamma delta cells, IL-2-producing cells are a subset of the GFP-expressing cells, whereas in TCR alpha beta cells, endogenous IL-2 is more likely to be expressed without GFP. These results are seen in multiple independent transgenic lines and thus reflect functional properties of the transgene sequences, rather than copy number or integration site effects. The high ratio of GFP: endogenous IL-2 gene expression in transgenic TCR gamma delta cells may be explained by subset-specific IL-2 gene regulatory elements mapping outside of the 8.4-kb transgene regulatory sequence, as well as accelerated kinetics of endogenous IL-2 RNA degradation in TCR gamma delta cells. The high levels and percentages of transgene expression in thymic and splenic TCR gamma delta and NKT cells, as well as skin TCR gamma delta-dendritic epidermal T cells, indicate that the IL-2-GFP-transgenic mice may provide valuable tracers for detecting developmental and activation events in these lineages.
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Mary A
authors.initials: MA
authors.lastname: Yui
authors.forename: Leslie L
authors.initials: LL
authors.lastname: Sharp
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Havran
authors.forename: Ellen V
authors.initials: EV
authors.lastname: Rothenberg
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D005333:Fetus; D005786:Gene Expression Regulation / Q000276:immunology*; D005787:Gene Frequency / Q000276:immunology; D005819:Genetic Markers / Q000276:immunology; D049452:Green Fluorescent Proteins; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism*; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D020871:RNA Stability / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis*; D012045:Regulatory Sequences, Nucleic Acid / Q000276:immunology*; D012867:Skin / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D019076:Transgenes / Q000276:immunology*
chemical_list: D005819:Genetic Markers; D007376:Interleukin-2; D008164:Luminescent Proteins; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D049452:Green Fluorescent Proteins