Lack of N regions in fetal and neonatal mouse immunoglobulin V-D-J junctional sequences.
Much of T and B lymphocyte receptor diversity derives from the addition of nontemplated N regions at the junctions of receptor gene elements, although fetal T cells expressing gamma/delta receptors lack N regions. I have sequenced immunoglobulin H chain variable regions of PCR-amplified DNA and cDNA from fetal and newborn mouse liver and spleen cells. These sequences showed an absence of N regions. Only 1/87 DNA sequences and 17/146 RNA sequences contained N regions, in striking contrast to adult Ig sequences. These data show that N region insertion is a developmentally regulated process in B cells as well as in T cells, and demonstrate that receptor diversity in neonatal B cells is limited by the absence of N regions as well as by biased usage of Vh genes.
Division of Immunology, Medical Biology Institute, La Jolla, California 92037.
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AJ
Feeney
D000818:Animals; D000831:Animals, Newborn / Q000276:immunology* / Q000378:metabolism; D001483:Base Sequence; D004247:DNA / Q000032:analysis / Q000235:genetics; D004251:DNA Transposable Elements; D005333:Fetus / Q000276:immunology* / Q000378:metabolism; D015321:Gene Rearrangement / Q000235:genetics*; D005803:Genes, Immunoglobulin / Q000235:genetics*; D007133:Immunoglobulin Joining Region / Q000235:genetics; D008099:Liver / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012313:RNA / Q000032:analysis / Q000235:genetics; D013154:Spleen / Q000737:chemistry
D004251:DNA Transposable Elements; D007133:Immunoglobulin Joining Region; D012313:RNA; D004247:DNA