Immunoglobin heavy chain isotype switch recombination is a regulated process of DNA deletion, which joins a rearranged and expressed variable region to a new downstream constant region, deleting the DNA between. Each class of constant regions removes antigen in a different way, so the result of switch recombination is to alter how an immunoglobulin molecule removes antigen without altering its specificity for antigen. Switch recombination plays a critical role in the immune response, and impaired switch recombination can result in immunodeficiency disease. The proposed research will study the molecular mechanism of switch recombination. (1) We will determine the function of the GQN1 nuclease in switch recombination; (2) we will ask if transcription of the G-rich S region sequences causes G4 DNA structures to form; (3) we will ask how mutation of the B cell-specific factor, LR1, affects switch recombination; (4) we will determine the roles of the recombination/repair factors Rad52 and Rad51 in switch recombination; and (5) we will visualize the S regions in recombining B cells to identify dynamic interactions during switch recombination. These experiments will define the molecular components of the switch recombination pathway. Results of these experiments will also have broader implications, because molecules and mechanisms critical to switch recombination have more general roles in maintaining genomic stability in mammalian cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM039799-18
Application #
6779103
Study Section
Mammalian Genetics Study Section (MGN)
Program Officer
Anderson, Richard A
Project Start
1988-04-01
Project End
2006-03-31
Budget Start
2004-08-01
Budget End
2006-03-31
Support Year
18
Fiscal Year
2004
Total Cost
$303,200
Indirect Cost
Name
University of Washington
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Yabuki, Munehisa; Cummings, W Jason; Leppard, John B et al. (2012) Antibody discovery ex vivo accelerated by the LacO/LacI regulatory network. PLoS One 7:e36032
Yabuki, Munehisa; Ordinario, Ellen C; Cummings, W Jason et al. (2009) E2A acts in cis in G1 phase of cell cycle to promote Ig gene diversification. J Immunol 182:408-15
Ordinario, Ellen C; Yabuki, Munehisa; Larson, Ryan P et al. (2009) Temporal regulation of Ig gene diversification revealed by single-cell imaging. J Immunol 183:4545-53
Vallur, Aarthy C; Maizels, Nancy (2008) Activities of human exonuclease 1 that promote cleavage of transcribed immunoglobulin switch regions. Proc Natl Acad Sci U S A 105:16508-12
Vallur, A C; Yabuki, M; Larson, E D et al. (2007) AID in antibody perfection. Cell Mol Life Sci 64:555-65
Maizels, Nancy (2006) Dynamic roles for G4 DNA in the biology of eukaryotic cells. Nat Struct Mol Biol 13:1055-9
Maizels, Nancy (2005) Immunoglobulin gene diversification. Annu Rev Genet 39:23-46
Larson, Erik D; Duquette, Michelle L; Cummings, W Jason et al. (2005) MutSalpha binds to and promotes synapsis of transcriptionally activated immunoglobulin switch regions. Curr Biol 15:470-4
Larson, Erik D; Cummings, W Jason; Bednarski, David W et al. (2005) MRE11/RAD50 cleaves DNA in the AID/UNG-dependent pathway of immunoglobulin gene diversification. Mol Cell 20:367-75
Yabuki, Munehisa; Fujii, Monica M; Maizels, Nancy (2005) The MRE11-RAD50-NBS1 complex accelerates somatic hypermutation and gene conversion of immunoglobulin variable regions. Nat Immunol 6:730-6

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