A pivotal role for DNase I-sensitive regions 3b and/or 4 in the induction of somatic hypermutation of IgH genes.
Chimeric mice were prepared from embryonic stem cells transfected with IgH genes as transgenes and RAG-2-deficient blastocysts for the purpose of identifying the cis-acting elements responsible for the induction of somatic hypermutation. Among the three transgene constructs used, the V(H) promoter, the rearranged V(H)-D-J(H), an intron enhancer/matrix attachment region, and human Cmu were common to all, but the 3'-untranslated region in each construct was different. After immunization of mice with a T cell-dependent Ag, the distribution and frequency of hypermutation in transgenes were analyzed. The transgene lacking the 3' untranslated region showed a marginal degree of hypermutation. Addition of the 3' enhancer resulted in a slight increase in the number of mutations. However, the transgene containing DNase I-sensitive regions 3b and 4 in addition to the 3' enhancer showed more than a 10-fold increase in hypermutation, reaching levels comparable to those observed in endogenous V(H)186.2 genes of C57BL/6 mice.
Terauchi
A
A
Division of Biosignaling, Research Institute for Biological Sciences, Science University of Tokyo, Yamazaki 2669, Noda, Chiba 278 0022, Japan.
Hayashi
K
K
Kitamura
D
D
Kozono
Y
Y
Motoyama
N
N
Azuma
T
T
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D002999:Clone Cells; D004252:DNA Mutational Analysis; D003850:Deoxyribonuclease I / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D019076:Transgenes / Q000276:immunology; D014407:Tumor Cells, Cultured
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D011993:Recombinant Fusion Proteins; D003850:Deoxyribonuclease I