Immunoglobulin heavy-chain enhancer requires one or more tissue-specific factors.
Enhancer sequences are regulatory regions that greatly increase transcription of certain eukaryotic genes. An immunoglobulin heavy-chain variable gene segment is moved from a region lacking enhancer activity to a position adjacent to the known heavy-chain enhancer early in B-cell maturation. In lymphoid cells, the heavy-chain and SV40 enhancers bind a common factor essential for enhancer function. In contrast, fibroblast cells contain a functionally distinct factor that is used by the SV40 but not by the heavy-chain enhancer. The existence of different factors in these cells may explain the previously described lymphoid cell specificity of the heavy-chain enhancer.
D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D002460:Cell Line; D004742:Enhancer Elements, Genetic; D005347:Fibroblasts / Q000276:immunology; D005809:Genes, Regulator; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics; D051379:Mice; D014158:Transcription, Genetic
D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region