title: Cutting edge: absence of expression of RAG1 in peritoneal B-1 cells detected by knocking into RAG1 locus with green fluorescent protein gene.
abstract: It has been proposed that Ig gene rearrangement in the peritoneal cavity (Pc) B-1 cells might be involved in autoantibody generation. To study possible secondary B cell maturation, we prepared mice carrying a target integration of gfp gene into a rag1 locus (rag1/gfp mice). The GFP+ cells express rag1 mRNA and are undergoing Ig gene rearrangement. RAG1 expression was studied in Pc B-1 cells to detect cells during the stage of Ig gene rearrangement. In contrast to previous reports, Pc B-1 cells did not show RAG1 expression in adolescent or elderly mice. RAG1 expression was not induced in Pc B-1 cells in vivo after stimulation by oral or i.p. administration of LPS. Our results suggest that RAG1 expression in Pc B-1 cells is inhibited for a long period under normal condition and that this suppression is an essential state which maintains allelic exclusion of Ig genes.
authors.affiliation: Department of Immunology, Kumamoto University School of Medicine, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kuwata
authors.forename: H
authors.initials: H
authors.lastname: Igarashi
authors.forename: T
authors.initials: T
authors.lastname: Ohmura
authors.forename: S
authors.initials: S
authors.lastname: Aizawa
authors.forename: N
authors.initials: N
authors.lastname: Sakaguchi
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D003433:Crosses, Genetic; D004254:DNA Nucleotidyltransferases / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics*; D005786:Gene Expression Regulation / Q000276:immunology*; D016654:Genes, RAG-1 / Q000276:immunology*; D005822:Genetic Vectors / Q000138:chemical synthesis / Q000378:metabolism; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics*; D019426:Integrases; D008164:Luminescent Proteins / Q000235:genetics*; D051379:Mice; D008817:Mice, Mutant Strains; D016254:Mutagenesis, Insertional; D010537:Peritoneum / Q000166:cytology; D012333:RNA, Messenger / Q000096:biosynthesis; D045522:Recombinases; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology
chemical_list: D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D012333:RNA, Messenger; D045522:Recombinases; C064658:RAG-1 protein; D049452:Green Fluorescent Proteins; D004254:DNA Nucleotidyltransferases; D019426:Integrases; C115006:integron integrase IntI1