title: Expression of immunoglobulin heavy chain at a high level in the absence of a proposed immunoglobulin enhancer element in cis.
abstract: The major intron between the J and C gene segments of the immunoglobulin heavy (H) chain locus contains an enhancer-like sequence, and it has been proposed that this enhancer is necessary to achieve high levels of H chain expression. We have isolated a subclone of the lymphoid pre-B cell line 18-81 that lacks this enhancer but nevertheless produces mu chain at the level characteristic of pre-B cells. Another subclone with a larger deletion does not produce mu chain, but upon fusion with a myeloma that does not produce any immunoglobulin chain, mu chain is expressed by the homolog from the pre-B subclone. The hybridoma lacks the proposed enhancer element in cis; nevertheless it produces as much mu chain as other plasma cell hybridomas. Therefore, this enhancer element is not obligatory for a high level of H chain production.
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002999:Clone Cells; D004247:DNA / Q000235:genetics*; D004262:DNA Restriction Enzymes; D005434:Flow Cytometry; D005796:Genes; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D051379:Mice; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D007143:Immunoglobulin Heavy Chains; D007148:Immunoglobulin mu-Chains; D012333:RNA, Messenger; D004247:DNA; D004262:DNA Restriction Enzymes