title: Regulation of transgenic class II major histocompatibility genes in murine Langerhans cells.
abstract: I-E is a class II major histocompatibility complex molecule normally expressed by Langerhans cells. A series of transgenic mice were developed previously that carry E alpha d gene constructs with promoter-region deletions that cause expression of I-E by different cell types when maintained on a B6 (I-E[-]) genetic background. To study cis-acting gene sequences that regulate expression of class II proteins by Langerhans cells, we identified transgenic I-E expression by tissue immunoperoxidase staining and by epidermal cell suspension immunofluorescence cytometry. Mice with a transgene containing 1.4 kilobase pairs (kb) of flanking sequence 5' to the E alpha initiation site expressed barely detectable levels of I-E on a tiny percentage of Langerhans cells, indicating that sequences promoting Langerhans cell expression of E alpha exist between 2.0 and 1.4 kb 5' of the E alpha initiation site. Removal of an additional 170 bp of 5' flanking sequence caused near-normal levels of expression by approximately one third of epidermal Langerhans cells, which contrasts with studies that showed minimal transgene expression by splenic dendritic cells in these animals. Thus, sequences between 1.4 and 1.23 kb 5' of the E alpha initiation site decrease expression of I-E by epidermal Langerhans cells, but enable I-E expression by splenic dendritic cells. These studies identify Langerhans cell-specific regulatory sequences and genetic regions controlling major histocompatibility complex class II gene expression in Langerhans cells and splenic dendritic cells. The genetic regions identified may be particularly important because differential regulation of class II major histocompatibility complex protein synthesis by Langerhans cells and dendritic cells may be crucial to immune functions of intact animals.
authors.affiliation: Department of Dermatology (Yale Skin Disease Research Center), Yale University School of Medicine, New Haven, CT 06520-8059.
authors.forename: J
authors.initials: J
authors.lastname: Longley
authors.forename: T G
authors.initials: TG
authors.lastname: Ding
authors.forename: D
authors.initials: D
authors.lastname: Levin
authors.forename: J
authors.initials: J
authors.lastname: Lewis
authors.forename: R
authors.initials: R
authors.lastname: Edelson
authors.forename: R
authors.initials: R
authors.lastname: Tigelaar
authors.forename: R
authors.initials: R
authors.lastname: Flavell
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000235:genetics; D003713:Dendritic Cells / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II; D016153:Genes, Suppressor; D007801:Langerhans Cells / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D013154:Spleen / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology
chemical_list: D000954:Antigens, Surface