Massachusetts General Hospital
Simches Research Ctr CPZN# 6620
185 Cambridge St.
Boston, MA 02114
The vertebrate immune system is capable of specifically recognizing and responding to an enormous number of antigens. The interaction with antigen is mediated by the immunoglobulin (Ig) and T cell receptor (TCR) molecules expressed by B and T lymphocytes, respectively. Ig and TCR genes are encoded by multiple segments of DNA that are not contiguous in the germ line but are joined together in developing lymphocytes by a process known as V(D)J recombination. This reaction generates much of the required diversity in he binding specificities of Igs and TCRs. These recombination events are highly regulated,with Ig segments, for example, rearranging in an ordered series and only in B cells, not T cells. My laboratory is interested in understanding all facets of this process: the enzymatic and regulatory machinery involved, the mechanism of the reaction, and the regulation of recombination events during lymphoid development. We previously isolated two recombination activating genes, RAG-1 and RAG-2, which induce V(D)J recombination when expressed in mouse fibroblasts that normally lack recombinase activity. Together purified RAG-1 and RAG-2 proteins are sufficient to carry out the initial steps of the recombination process in vitro. These two proteins recognize the recombination signal sequences that flank antigen receptor gene segments, and then specifically cleave the DNA at this site in a two-step process. We are now actively pursuing a number of experimental paths, both biochemical and genetic, aimed at further understanding the specific functions of these proteins, what factors are required to complete the reaction, and how the regulation seen in developing B and T cells is imposed.
Morshead, K. B., Ciccone, D. N., Taverna, S. D., Allis, C. D., and Oettinger, M. A. (2003). Antigen receptor loci poised for V(D)J rearrangement are broadly associated with Brg1 and flanked by peaks of histone H3 dimethylated at lysine 4. Proc. Natl. Acad. Sci. U S A. 100:11577-11582.
Clatworthy, A. E, Valencia, M. A, Haber, J. E, and Oettinger, M. A. (2003) V(D)J recombination and RAG-mediated transposition in yeast. Mol. Cell 12:489-499.
Elkin, S. K., Matthews, A. G., and Oettinger, M. A. (2003). The C-terminal portion of RAG2 protects against transposition in vitro. EMBO J. 22:1931-1938.
Last Update: 1/6/2014