To mount an optimum immune response, mature B lymphocytes undergo two genetic alterations in the forms of class switch recombination (CSR) and somatic hypermutation (SHM). CSR leads to the production of antibodies of various isotypes (IgG, IgE, IgA) while SHM results in the generation of antibody molecules with a much higher affinity for antigens. The B cell specific protein AID (activation induced deaminase) is essential to both processes. AID initiates CSR and SHM by deaminating cytidines within transcribed regions of the immunoglobulin locus. These lesions are then converted into point mutations during SHM or into DNA double strand breaks that serve as obligatory intermediates during CSR. Inactivation of AID leads to human immunodeficiency syndromes (Hyper-IgM2) where patients suffer from profound susceptibility to bacterial infections. On the other hand, deregulation of AID converts it into a general mutator and leads to mutations and translocations of oncogenes that have been implicated in mature B cell lymphomagenesis. An understanding of the processes that regulate AID activity is thus of utmost importance. The overall objective of this research proposal is to elucidate the mechanism by which AID activity is regulated during CSR and SHM. Recent studies have shown that protein kinase A (PKA) phosphorylates AID in vitro to activate its ability to bind its cofactor, the single-stand DNA binding protein Replication Protein A and mediate deamination of transcribed DNA substrates. To elucidate the role of AID phosphorylation in vivo, mice with a mutation in the AID phosphorylation site will be generated and analyzed for CSR and SHM. The mutant mouse will also be used in cellular and biochemical assays to delineate the function of phosphorylated AID in CSR and SHM. Finally, existing PKA mutants will be analyzed to test the hypothesis that AID phosphorylation by PKA is itself a highly regulated event and could potentially contribute to AID target specificity. Successful completion of the projects outlined in this proposal will provide mechanistic insights into reactions central to immunity and how aberrations in such physiological reactions can cause mature B cell tumors.

Public Health Relevance

TO PUBLIC HEALTH B cell lymphomas are the most common human malignancies. It is now clear that a large majority of B cell tumors arise due to mistargeted AID activity. Experiments proposed here will elucidate the role of AID in both immunity and cancer.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI072194-04
Application #
8284486
Study Section
Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Nasseri, M Faraz
Project Start
2009-07-01
Project End
2014-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
4
Fiscal Year
2012
Total Cost
$464,567
Indirect Cost
$219,542
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
Balestrini, Alessia; Nicolas, Laura; Yang-Lott, Katherine et al. (2016) Defining ATM-Independent Functions of the Mre11 Complex with a Novel Mouse Model. Mol Cancer Res 14:185-95
DiMenna, Lauren J; Chaudhuri, Jayanta (2016) Regulating infidelity: RNA-mediated recruitment of AID to DNA during class switch recombination. Eur J Immunol 46:523-30
Pucella, Joseph N; Yen, Wei-Feng; Kim, Myoungjoo V et al. (2015) miR-182 is largely dispensable for adaptive immunity: lack of correlation between expression and function. J Immunol 194:2635-42
Zheng, Simin; Vuong, Bao Q; Vaidyanathan, Bharat et al. (2015) Non-coding RNA Generated following Lariat Debranching Mediates Targeting of AID to DNA. Cell 161:762-73
Matthews, Allysia J; Zheng, Simin; DiMenna, Lauren J et al. (2014) Regulation of immunoglobulin class-switch recombination: choreography of noncoding transcription, targeted DNA deamination, and long-range DNA repair. Adv Immunol 122:1-57
Matthews, Allysia J; Husain, Solomon; Chaudhuri, Jayanta (2014) Binding of AID to DNA does not correlate with mutator activity. J Immunol 193:252-7
Vuong, Bao Q; Herrick-Reynolds, Kayleigh; Vaidyanathan, Bharat et al. (2013) A DNA break- and phosphorylation-dependent positive feedback loop promotes immunoglobulin class-switch recombination. Nat Immunol 14:1183-9
Nicolás, Laura; Chaudhuri, Jayanta (2013) 4C-ing the Igh Landscape. Immunity 39:199-201
Kumar, Ritu; DiMenna, Lauren; Schrode, Nadine et al. (2013) AID stabilizes stem-cell phenotype by removing epigenetic memory of pluripotency genes. Nature 500:89-92
Vuong, Bao Q; Chaudhuri, Jayanta (2012) Combinatorial mechanisms regulating AID-dependent DNA deamination: interacting proteins and post-translational modifications. Semin Immunol 24:264-72

Showing the most recent 10 out of 13 publications