Germinal center B cells undergo a high rate of somatic mutation and recombination of their immunoglobulin genes that is responsible for the affinity maturation and isotype switching that generates protective antibodies. These processes are initiated by activation induced cytidine deaminase which generates G:U mismatches that are processed by replication, base excision repair and mismatch repair to produce the mutations required for somatic hypermutation of antibody variable and switch regions. Mismatch repair is responsible for ~60% of the total mutations and most of the mutations in A:T bases that lead to production of more effective antibodies. While mismatch repair normally maintains the integrity and stability of the genome, at the Ig gene it mediates extensive mutation and recombination. Here we propose to examine how germinal center B cells use mismatch repair to recruit error prone repair to specific regions of the immunoglobulin genes while continuing to maintain genomic stability in the rest of genome and to examine role of mismatch repair in the B cell lymphomagenesis. We will do this by: 1) determining how MSH6 and the other mismatch repair proteins interact with PCNA to recruit error prone repair to the immunoglobulin variable and switch regions, but not to other genes in mutating and switching germinal center B cells;2) comparing the interactions of the mismatch repair proteins with each other and with other proteins in mutating and switching B cells and with those interactions in other types of cells;and 3) examining the characteristics of the lymphomas that arise in MSH6 deficient and mutant mice in order to understand how MSH6 protects B cells from lymphomagenesis.

Public Health Relevance

To protect us from pathogenic organisms, it is necessary for us to produce antibodies to every possible antigen and to rapidly change those antibodies as the pathogen changes. We do this by introducing many mutations into the genes that encode the antibody molecules as we respond to infection and this genetic instability is accomplished mostly through a process called mismatch repair. We will use mice that have genetic defects in mismatch repair to examine how the generation of antibody diversity is accomplished.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA102705-08
Application #
8001994
Study Section
Cellular and Molecular Immunology - B Study Section (CMIB)
Program Officer
Mccarthy, Susan A
Project Start
2003-07-01
Project End
2013-12-31
Budget Start
2011-01-01
Budget End
2011-12-31
Support Year
8
Fiscal Year
2011
Total Cost
$314,906
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
110521739
City
Bronx
State
NY
Country
United States
Zip Code
10461
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