title: Functional and molecular analysis of the double-positive stage-specific CD8 enhancer E8III during thymocyte development.
abstract: Several developmental stage-, subset-, and lineage-specific Cd8 cis-regulatory regions have been identified. These include the E8(III) enhancer, which directs expression in double-positive (DP) thymocytes, and E8(II), which is active in DP cells and CD8(+) T cells. Using a transgenic reporter expression assay, we identified a 285-bp core fragment of the E8(III) enhancer that retains activity in DP thymocytes. In vitro characterization of the core enhancer revealed five regulatory elements that are required for full enhancer activity, suggesting that multiple factors contribute to the developmental stage-specific activity. Furthermore, deletion of E8(III) in the mouse germline showed that this enhancer is required for nonvariegated expression of CD8 in DP thymocytes when E8(II) is also deleted. These results indicate that E8(III) is one of the cis-elements that contribute to the activation of the Cd8a and Cd8b gene complex during T cell development.
authors.affiliation: Institute of Immunology, Medical University Vienna, Vienna, Austria.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Feik
authors.forename: Ivan
authors.initials: I
authors.lastname: Bilic
authors.forename: Johanna
authors.initials: J
authors.lastname: Tinhofer
authors.forename: Bernd
authors.initials: B
authors.lastname: Unger
authors.forename: Dan R
authors.initials: DR
authors.lastname: Littman
authors.forename: Wilfried
authors.initials: W
authors.lastname: Ellmeier
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D015704:CD4 Antigens / Q000096:biosynthesis*; D016827:CD8 Antigens / Q000096:biosynthesis* / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D024721:E-Box Elements / Q000235:genetics; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D017353:Gene Deletion; D005786:Gene Expression Regulation; D018390:Gene Targeting; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic / Q000235:genetics; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; C431698:CD8alpha antigen; D020598:Proto-Oncogene Proteins c-myb