title: The human immunoglobulin C mu-C delta locus: complete nucleotide sequence and structural analysis.
abstract: The entire nucleotide sequence (approximately 20 kbp) spanning the human immunoglobulin IgM (mu) and IgD (delta) heavy chain constant region genes has been determined from DNA of mu-delta producing chronic lymphocytic leukemic B cells. As in the murine IgM + IgD double-producing B cells, no rearrangement has occurred in the C mu-C delta region in the leukemic cells. The C mu locus is highly conserved between mouse and human with the exception of the nucleotide sequence between the C mu 4 and mu M1 exons, which has diverged dramatically. The intergenic sequence between human C mu and C delta is three times larger than the analogous region in the mouse and contains notable features absent from the mouse, including a 443 bp segment that is 96% identical to a 442 bp sequence that occurs just 3' to the heavy chain enhancer, a 366 bp sequence that is directly repeated with 76% homology, and 12 tandem copies of a 35 bp sequence. The human C delta gene contains two additional exons relative to mouse C delta, but shares with the mouse the unique distal location of both secreted and membrane coding segments. Several polymorphisms in the human population have been identified in the intergenic region and in C delta but not in C mu.
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: C J
authors.initials: CJ
authors.lastname: Word
authors.forename: M B
authors.initials: MB
authors.lastname: White
authors.forename: W A
authors.initials: WA
authors.lastname: Kuziel
authors.forename: A L
authors.initials: AL
authors.lastname: Shen
authors.forename: F R
authors.initials: FR
authors.lastname: Blattner
authors.forename: P W
authors.initials: PW
authors.lastname: Tucker
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D005803:Genes, Immunoglobulin; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007138:Immunoglobulin delta-Chains / Q000235:genetics; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D013045:Species Specificity
chemical_list: D007127:Immunoglobulin Constant Regions; D007138:Immunoglobulin delta-Chains; D007148:Immunoglobulin mu-Chains; D004247:DNA