Rearrangements and deletions of immunoglobulin heavy chain genes in the double-producing B cell lymphoma I. 29
The B cell lymphoma I.29 consists of a mixture of cells expressing membrane-bound immunoglobulin M (IgM) (lambda) and IgA (lambda) of identical idiotypes. Whereas most of the cells express either IgM of IgA alone, 1 to 50% of the cells in this tumor express IgM and IgA simultaneously within the cytoplasm and on the cell membrane. When IgM/sup +/ cells are purified from the lymphoma and passaged in mice or cultured, a portion of the cells convert to IgA/sup +/. These properties suggest that some cells of the I.29 lymphoma may undergo immunoglobulin heavy chain switching, although it is also possible that the mixed population was derived by a prior switching event in a clone of cells. The authors performed Southern blotting experiments on genomic DNAs isolated from populations of I.29 cells containing variable proportions of IgM/sup +/ and IgA/sup +/ cells and on a number of cell lines derived from the lymphoma. The results were consistent with the deletion model for heavy chain switching, as the IgM/sup +/ cells contained rearranged ..mu.. genes and ..cap alpha..genes in the germ line configuration on both the expressed and nonexpressed heavy chain chromosomes, whereas the IgA/sup +/ cells had deleted both ..mu.. genes and contained one rearranged and one germ line ..cap alpha..gene. In addition, segments of DNA located within the intervening sequence 5' to the ..mu..gene, near the site of switch recombination, were deleted from both the expressed and the nonexpressed chromosomes. Although ..mu.. genes were deleted from both chromosomes in the IgA/sup +/ cells, the sites of DNA recombination differed on the two chromosomes. On the expressed chromosome, S..mu.. sequences were recombined with S..cap alpha.. sequences, whereas on the nonexpressed chromosome, S..mu.. sequences were recombined with S..gamma..3 sequences.
- Research Organization:
- Molecular Biology and Genetics Unit of the Graduate School for Medical Sciences, Sloan-Kettering Div., New York, NY 10021
- OSTI ID:
- 5856135
- Journal Information:
- Mol. Cell. Biol.; (United States), Vol. 2:8
- Country of Publication:
- United States
- Language:
- English
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SURFACE PROPERTIES
IMMUNOGLOBULINS
BIOSYNTHESIS
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STRUCTURE-ACTIVITY RELATIONSHIPS
LYMPHOCYTES
BIOLOGICAL FUNCTIONS
LYMPHOMAS
CELL DIFFERENTIATION
BIOLOGICAL MODELS
CELL CULTURES
CHROMOSOMAL ABERRATIONS
CLONE CELLS
DNA SEQUENCING
GENE RECOMBINATION
GENE REGULATION
GENETIC MAPPING
GERM CELLS
MEMBRANE PROTEINS
MICE
ONCOGENIC TRANSFORMATIONS
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BODY FLUIDS
CELL CONSTITUENTS
CELL TRANSFORMATIONS
CONNECTIVE TISSUE CELLS
DISEASES
FUNCTIONS
GLOBULINS
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MAPPING
MATERIALS
MEMBRANES
MUTATIONS
NEOPLASMS
ORGANIC COMPOUNDS
PROTEINS
RODENTS
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STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
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550400* - Genetics
550200 - Biochemistry