Germ‐line transcription occurs on both the functional and the non‐functional alleles of immunoglobulin constant heavy chain genes

• Published in: European journal of immunology 2003-08, Vol.33 (8), p.2108-2113
• Main Authors: Delpy, Laurent, Le Bert, Marc, Cogné, Michel, Khamlichi, Ahmed Amine
• Format: Article
• Language: English
• Subjects: Alleles; Animals; B-Lymphocytes; B-Lymphocytes - immunology; B cell; Cells, Cultured; Class switch recombination; Gene Silencing; Gene Targeting; Genes, Immunoglobulin; Gene‐targeted mice; Germ‐line transcription; Immunoglobulin Class Switching; Immunoglobulin Constant Regions; Immunoglobulin Constant Regions - genetics; Immunoglobulin heavy chain locus; Immunoglobulin Heavy Chains; Immunoglobulin Heavy Chains - genetics; Immunology; Life Sciences; Mice; Mice, Knockout; Transcription, Genetic
• ISSN: 0014-2980; 1521-4141
• DOI: 10.1002/eji.200323969

In B cells undergoing class switching, recombination is usually directed to the same switch sequences on both homologous chromosomes and is generally preceded by germ‐line transcription initiated from I promoters upstream of immunoglobulin constant heavy chain genes. Whether germ‐line transcription occurs on both alleles or is restricted to the productive one has not been directly addressed before. To clearly distinguish between these two possibilities, a system is needed in which one might detect allele‐specific germ‐line transcripts. We used homologous recombination to set up twoin vivo systems in which one γ3 allele was marked by a loxP sequence whereas the other allele was silenced by inhibiting μ heavy chain production. Here, we provide evidence that germ‐line transcription occurs on both the functional and the non‐functional alleles.