The long term goal of this physician-scientist grant proposal is to develop the skills required to understand the mechanisms by which B lymphocytes undergo and regulate immunoglobulin (Ig) gene somatic hypermutation. This process allows for generation of greater antibody diversity and development of more effective higher affinity antibodies. Previous attempts to study the molecular mechanisms and detailed organization of this process have been hampered by the lack of an appropriate B cell model for this process. Evidence exists for high frequency mutations of the variable region heavy chain Ig gene of a subclone of 18.81, an Abelson-transformed murine pre-B cell line. During Phase I of this project, in addition to coursework in molecular biology, will be the confirmation that the 18.81 cell line undergoes frequent and spontaneous point mutations in the variable (V) region of its endogenous immunoglobulin gene and that the frequency of V region mutation is greater than constant region mutation. Practical serological and molecular assays will be established to identify mutant genes. Comparisons will be performed of the rate and nature of mutations that occur in transfected and endogenous Ig genes. In Phase II, transfected constructs of an Ig gene will be used to determine DNA sequences in the flanking and/or coding sequences which are required for mutations to occur and to see if specific sequences are targeted for these events. Those sequences shown to be important for this process will be analyzed by site directed mutagenesis and will be used to search for proteins involved in the regulation of this process by gel retardation assay. Their relevance in vivo will be examined using transgenic mice. Genes for these proteins will be cloned for determination of sequence, expression, and in this in vitro system. Determination of the mechanism and regulation of this process would resolve one of the major mechanisms for generating antibody diversity. It would also allow the generation of higher affinity monoclonal antibodies such as those used for anti- neoplastic or infectious processes and for diagnostic purposes. Mutations in the Ig gene are important in the oncogenesis of malignancies such as Burkitt's lymphoma. Improved understanding of this process may lead to novel treatments for these and other lymphoid tumors, and for manipulation of lymphoid cell differentiation.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Physician Scientist Award (K11)
Project #
1K11CA001635-01
Application #
3085951
Study Section
Cancer Institutional Fellowship Review Committee (CT)
Project Start
1992-07-01
Project End
1997-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
1
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Type
Schools of Medicine
DUNS #
009095365
City
Bronx
State
NY
Country
United States
Zip Code
10461
Maschi, Tina; Morgen, Keith; Hatcher, Schnavia Smith et al. (2009) Maltreated children's thoughts and emotions as behavioral predictors: evidence for social work action. Soc Work 54:135-43
Cicchetti, D; Rogosch, F A (1999) Psychopathology as risk for adolescent substance use disorders: a developmental psychopathology perspective. J Clin Child Psychol 28:355-65
Green, N S; Lin, M M; Scharff, M D (1998) Somatic hypermutation of antibody genes: a hot spot warms up. Bioessays 20:227-34
Sack, S Z; Liu, Y; German, J et al. (1998) Somatic hypermutation of immunoglobulin genes is independent of the Bloom's syndrome DNA helicase. Clin Exp Immunol 112:248-54
Lin, M M; Green, N S; Zhang, W et al. (1998) The effects of E mu, 3'alpha (hs 1,2) and 3'kappa enhancers on mutation of an Ig-VDJ-Cgamma2a Ig heavy gene in cultured B cells. Int Immunol 10:1121-9
Green, N S; Verdugo, G; Getman, M E et al. (1997) Ig V region hypermutation in B cell hybrids mimics in vivo mutation and allows for isolation of clonal variants. Mol Immunol 34:1095-103
Scharff, M D; Poltoratsky, V; Green, N S (1997) The promotion of V region hypermutation. J Exp Med 185:185-8
Lin, M; Chang, C J; Green, N S (1996) A new method for estimating high mutation rates in cultured cells. Mutat Res 351:105-16
Green, N S; Rabinowitz, J L; Zhu, M et al. (1995) Immunoglobulin variable region hypermutation in hybrids derived from a pre-B- and a myeloma cell line. Proc Natl Acad Sci U S A 92:6304-8