The DJH complex remains active in recombination to VH segments after the loss of mu-chain expression in mu-positive pre-B cells.
AT11-2 is an Abelson virus-transformed B precursor cell line which is capable of differentiating Ig- from mu+ cells via functional recombination of VH segments to preexisting DJH complexes. We describe here that after a mu+ subclone (VDJ+/DJ) generated from Ig- AT11-2 (DJ/DJ) cells by in vitro functional VH to DJH recombination subsequently lost mu-chain expression either by the recombination of a pseudo VH segment to the VHDJH+ allele or by the deletion of VHDJH+ allele, a novel productive joining of VH segments to the preexisting DJH complex occurred. These results indicated that VH to VHDJH rearrangement was not suppressed in mu-chain producing cells and that the DJH complexes still remained active in the recombination to VH segments after the loss of mu-chain expression. Our results may also suggest that VH to DJH rearrangement, but not VH to VHDJH rearrangement, is suppressed in mu-chain producing cells to maintain allelic exclusion. Our cell differentiation system should continue to be valuable for elucidating the mechanism of suppression and associated implications regarding allelic exclusion.
Maeda
T
T
Third Department of Internal Medicine, Osaka University Medical School, Japan.
Sugiyama
H
H
Tani
Y
Y
Kishimoto
S
S
D000595:Amino Acid Sequence; D000818:Animals; D000916:Antibody Diversity; D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D015139:Blotting, Southern; D002461:Cell Line, Transformed; D003001:Cloning, Molecular; D015322:Gene Rearrangement, B-Lymphocyte; D005803:Genes, Immunoglobulin; D007143:Immunoglobulin Heavy Chains / Q000235:genetics* / Q000302:isolation & purification; D007133:Immunoglobulin Joining Region / Q000235:genetics* / Q000302:isolation & purification; D007148:Immunoglobulin mu-Chains / Q000235:genetics* / Q000302:isolation & purification; D051379:Mice; D008969:Molecular Sequence Data; D013234:Stem Cells / Q000378:metabolism*
D007143:Immunoglobulin Heavy Chains; D007133:Immunoglobulin Joining Region; D007148:Immunoglobulin mu-Chains