title: Regulation of RAG-2 protein expression in avian thymocytes.
abstract: The recombinase-activating genes, RAG-1 and RAG-2, have been shown to be necessary to initiate the process of V(D)J recombination during the ontogeny of lymphocytes. While much is known about the end products of this rearrangement process, little is known about the function or regulation of the components of the recombinase system. To this end, we have generated a monoclonal antibody to the chicken RAG-2 protein. Chicken thymocytes were found to express high levels of RAG-2, part of which is phosphorylated. Within thymocytes, RAG-2 is expressed primarily within the nucleus. RAG-2 protein levels are high in the CD4- CD8- and CD4+ CD8+ immature thymocytes but absent at the single-positive CD4+ CD8- or CD4- CD8+ stage of thymocyte development. Mitogenic stimulation of thymocytes with phorbol myristate acetate and ionomycin results in down-regulation of RAG-2 expression. Consistent with these data, in vivo levels of RAG-2 are markedly lower in proliferating thymocytes than in smaller, G0/G1 cells. Down-regulation of RAG-2 expression appears to occur before cells enter S phase, suggesting that RAG-2 function may be limited to noncycling cells.
authors.affiliation: Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Illinois.
authors.forename: S E
authors.initials: SE
authors.lastname: Ferguson
authors.forename: M A
authors.initials: MA
authors.lastname: Accavitti
authors.forename: D D
authors.initials: DD
authors.lastname: Wang
authors.forename: C L
authors.initials: CL
authors.lastname: Chen
authors.forename: C B
authors.initials: CB
authors.lastname: Thompson
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001483:Base Sequence; D002454:Cell Differentiation; D002469:Cell Separation; D048429:Cell Size; D002645:Chickens; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation / Q000235:genetics; D015322:Gene Rearrangement, B-Lymphocyte; D015759:Ionomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011506:Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D013347:Subcellular Fractions / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; C064655:V(D)J recombination activating protein 2; D015759:Ionomycin; D004247:DNA; D013755:Tetradecanoylphorbol Acetate