Gender	Female
E-mail	patricia.cortes@mssm.edu
Education and Training	PhD, UMDNJ Robert Wood Johnson Medical School

Education and Training	PhD, UMDNJ Robert Wood Johnson Medical School

Mechanism and Regulation of Immunoglobulin Genes Rearrangements
V(D)J recombination takes place during lymphocyte development and is the only site-specific recombination process thus far identified in vertebrates. Aberrant V(D)J recombination events have profound effects in vivo, and have been suggested as the cause of numerous lymphomas and leukemias. Antigen receptor gene assembly is directed by consensus recombination signal sequences and the reaction can be separated into four steps: recognition and cleavage of the DNA followed by processing and joining of the cleaved DNA ends. The joining reaction is essential for antigen receptor gene assembly as well as to maintain chromosomal integrity. The early steps of recognition and cleavage of the recombination signal sequences are mediated by the products of the recombination activating genes 1 and 2 (RAG1 andRAG2). Inactivation of the RAG1 or RAG2 gene in either human or mouse results in a severe combined immunodeficiency. Despite rapid progress in understanding the recognition and cleavage steps of V(D)J recombination the molecular mechanisms that govern processing and joining of the ends remain largely obscure. Despite the apparent complexity of the reaction only four proteins have been implicated in the joining process: DNA-PKcs, Ku, XRCC4 and ligase IV. These factors are known to be essential for both DNA double-strand break repair and V(D)J joining. The major stumbling block in understanding the molecular mechanism that mediates processing and joining of the DNA ends during V(D)J recombination was the lack of in vitro systems to study these reactions. We have now developed different cell free systems capable of catalyzing processing of hairpin end intermediates as well as formation and joining of coding and signal ends. We plan to use these newly developed in vitro systems to detail the molecular events that occur during V(D)J recombination by characterizing the intermediates and products of the reaction as well as the proteins involved in each step. As V(D)J recombination and DNA double strand break repair are rapidly converging and it is clear that they share a number of factors, our studies will contribute to the understanding of both of these important processes.

Spanopoulou E, Cortes P, Shih C, Huang E, Silver DP, Svec P, Baltimore D. Localization, interaction and RNA binding properties of the V(D)J recombinase-activating proteins RAG-1 and RAG-2. Immunity 1995 Dec; 3(6): 715-26.

Cortes P, Weis-Garcia F, Misulovin Z, Nussenzweig A, Lai JS, Li G, Nussenzweig MC, Baltimore D. In vitro V(D)J recombination: signal joint formation. Proc Natl Acad Sci U S A 1996 Nov 26; 93(24): 14008-13.

Weis-Garcia F, Besmer E, Sawchuk DJ, Yu W, Hu Y, Cassard S, Nussenzweig MC, Cortes P. V(D)J recombination: in vitro coding joint formation. Mol Cell Biol 1997 Nov; 17(11): 6379-85.

Sawchuk DJ, Weis-Garica F, Malik S, Besmer E, Bustin M, Nussenzweig MC, Cortes P. V(D)J recombination: Modulation of RAG1 and RAG2 cleavege activity on 12/23 substrates by whole cell extract and DNA-bending proteins. J Exp Med 1997 Jun 2; 185(11): 2025-32.

Besmer E, Mansilla-Soto J, Cassard S, Sawchuk DJ, Brown G, Sadofsky M, Lewis SM, Nussenzweig MC, Cortes P. Hairpin coding end opening is mediated by RAG1 and RAG2 proteins. Mol Cell 1998 Dec; 2(6): 817-28.

Reinberg D, Orphanides G, Ebright R, Akoulitchev S, Carcamo J, Cho H, Cortes P, Drapkin R, Flores O, Ha I, Inostroza JA, Kim S, Kim TK, Kumar P, Lagrange T, LeRoy G, Lu H, Ma DM, Maldonado E, Merino A, Mermelstein F, Olave I, Sheldon M, Shiekhattar R, Zawel L, Et Al . The RNA Polymerase II General Transcription Factors: Past, Present and Future. Cold Spring Harb Symp Quant Biol 1998 63:83-103.

Santagata S, Besmer E, Villa A, Bozzi F, Allingham JS, Sobacchi C, Haniford DB, Nussenzweig MC, Cortes P. The RAG1/RAG2 complex constitutes a 3' flap endonuclease: implications for junctional diversity in V(D)J and transpositional recombination. Mol Cell 1999 Dec; 4(6): 935-47.

Gomez C, Ptaszek L, Villa A, Bozzi F, Sobacchi C, Brooks EG, Notarangelo LD, Spanopoulou E, Vezzoni P, Cortes P, Santagata S. Mutations in conserved regions of the predicted RAG2 kelch repeats block initiation of V(D)J recombination and result in primary immunodeficiencies. Mol Cell Biol 2000 Aug; 20(15): 5653-64.