Antigen receptors are assembled from their component gene segments by a series of highly regulated site- specific DNA recombination reactions known as V(D)J recombination. The over-arching goal ofthis research program is to understand in molecular detail the mechanisms underlying the regulation ofthe V(D)J recombinase.Two lymphocyte restricted proteins, RAGl and RAG2 form a complex with one another and recognize pairs ofrecombination signal sequences (RSSs) that flank rearranging gene segments. The RAGs first nick the DNA then introduce dsDNA breaks. Appropriate broken ends are then joined to each other through the action of DNA repair proteins resulting in the formation ofcoding and signal joints. Targeting ofthe recombinase correlates with transcription ofthe unrearranged gene segments and is regulated at the level of RSS accessibility within chromatin structure. Errors in recombinase targeting are associated with chromosomal translocations that result in lymphoid malignancy and defects in V(D)J recombination result in immunodefiency. We propose to 1) test the idea that a gradient of H3K4me3 modified chromatin positioned by the distal germline k promoter determines the efficiency of Igk locus recombination and is important for allelic exclusion;2) perform a retroviral cDNA library screen for chromatin modifiers that influence recombination;3) use new high throughput DNA sequencing technologies to extend our studies ofssDNA nicking and RSS end insertion during V(D)J recombination in vivo;4) examine in detail how a critical transcription factor, E2A, alters chromatin structure to promote recombination in the Igk locus;5) use gene targeting to delete a CTGF binding site in a DNAse I sensitive region in between the IgHC V and D gene segments in order to test whether it regulates V-to-D rearrangement;and 6) test the h5T)othesis that the interaction between upstream promoters and downstream enhancers is necessary to promote coding joint formation by holding broken coding ends together. V(D)J recombination has been extensively studied using biochemical systems. Our approach is to take what has been learned in vitro and use it to frame and test hypotheses regarding the regulation of recombination in vivo.

Public Health Relevance

The genes encoding receptors in the immune system that recognize infectious microbes are spliced together by mixing and matching individual gene segments to create different receptor genes in each immune system cell. The goal of our studies is to understand the mechanisms that cells use to assemble these receptor genes. Errors in this system result in chromosomal translocations associated with leukemia and lymphoma and defect in this system result in inherited immunodeficiency diseases

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
4R37AI040227-15
Application #
7790937
Study Section
Special Emphasis Panel (NSS)
Program Officer
Nasseri, M Faraz
Project Start
1996-07-01
Project End
2015-05-31
Budget Start
2010-06-01
Budget End
2011-05-31
Support Year
15
Fiscal Year
2010
Total Cost
$419,005
Indirect Cost
Name
University of California Berkeley
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
124726725
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Vettermann, Christian; Timblin, Greg A; Lim, Vivian et al. (2015) The proximal J kappa germline-transcript promoter facilitates receptor editing through control of ordered recombination. PLoS One 10:e0113824
Chow, Kwan T; Schulz, Danae; McWhirter, Sarah M et al. (2013) Gfi1 and gfi1b repress rag transcription in plasmacytoid dendritic cells in vitro. PLoS One 8:e75891
Timblin, Greg A; Schlissel, Mark S (2013) Ebf1 and c-Myb repress rag transcription downstream of Stat5 during early B cell development. J Immunol 191:4676-87
Degner, Stephanie C; Verma-Gaur, Jiyoti; Wong, Timothy P et al. (2011) CCCTC-binding factor (CTCF) and cohesin influence the genomic architecture of the Igh locus and antisense transcription in pro-B cells. Proc Natl Acad Sci U S A 108:9566-71
Guo, Chunguang; Yoon, Hye Suk; Franklin, Andrew et al. (2011) CTCF-binding elements mediate control of V(D)J recombination. Nature 477:424-30
Sukumar, Selvakumar; Schlissel, Mark S (2011) Receptor editing as a mechanism of B cell tolerance. J Immunol 186:1301-2
Vettermann, Christian; Schlissel, Mark S (2010) Allelic exclusion of immunoglobulin genes: models and mechanisms. Immunol Rev 237:22-42
Hewitt, Susannah L; Farmer, Deborah; Marszalek, Katarzyna et al. (2008) Association between the Igk and Igh immunoglobulin loci mediated by the 3'Igk enhancer induces 'decontraction'of the Igh locus in pre-B cells. Nat Immunol 9:396-404
Bates, Jamie Geier; Cado, Dragana; Nolla, Hector et al. (2007) Chromosomal position of a VH gene segment determines its activation and inactivation as a substrate for V(D)J recombination. J Exp Med 204:3247-56
Curry, John D; Schulz, Danae; Guidos, Cynthia J et al. (2007) Chromosomal reinsertion of broken RSS ends during T cell development. J Exp Med 204:2293-303

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