The recombination mediated by double-strand breaks in extrachromosomal DNA substrate carrying mouse immunoglobulin switch regions S mu and S gamma 2b.
Recombination in mouse cells was analyzed using extrachromosomal DNA substrates carrying the mouse immunoglobulin switch regions S mu and S gamma 2b. Recombination was detected at a frequency of 10(-2)-10(-3) in mouse fibroblasts and in pre-B cell lines, but at a low frequency in a scid fibroblast cell line. Restriction enzyme digestion profile revealed that most recombination occurred between the CMV promoter region, which neighbors the S mu upstream region, and the S gamma 2b region. However, frequency of direct recombination between the CMV promoter region and the S gamma 2b region was low as measured by the substrate-lacking S mu region. Nucleotide sequence analysis showed that recombination occurred between several homologous base-pairs, and extranucleotides were frequently found at the recombination junctions. These results indicate that recombination took the form of the recombination mediated by double-strand breaks. Double-strand breaks likely occurred in the S mu and/or S gamma 2b region, and the ends joined.
Kameyama
K
K
Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Japan. K2@teine.chem2.hokudai.ac.jp
Sakaguchi
G
G
Haga
H
H
Shibata
N
N
Uryu
M
M
Sugimoto
K
K
D000818:Animals; D001402:B-Lymphocytes; D001482:Base Composition; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000737:chemistry / Q000235:genetics*; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005347:Fibroblasts; D007134:Immunoglobulin Switch Region / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011995:Recombination, Genetic
D004247:DNA; D004262:DNA Restriction Enzymes